Polarity judging arrangement by using frame synchronization signals of a received signal

Claim 2

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than two, the first frame of each multiframe comprising a multiframe synchronization signal representative of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal representative of a second predetermined synchronization word and another transmission data signal which succeeds said frame synchronization signal, said second predetermined synchronization word being defined by inverting said first predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; and counting means connected to said first and said second synchronization word detecting means and having an initial value, an upper threshold value, and a lower threshold value, said upper threshold value being higher than said initial value by a preselected value M, where M represents a second integer greater than one, said lower threshold value being lower than said initial value by said preselected value, said counting means being for counting down and up a count in response to said first and said second detection pulses, respectively, to produce said first and said second judgement result signals when said count increases up to said upper threshold value and when said count decreases down to said lower threshold value, respectively.

Claim 3

A polarity judging arrangement as claimed in claim 1, further comprising: count stopping means connected to said counting means for stopping said counting means in response to one of said first and said second judgement result signals to make said counting means continuously produce said one of the first and the second judgement result signals after reception of said one of the first and the second judgement result signals.

Claim 4

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than two, the first frame of each multiframe comprising a multiframe synchronization signal representative of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal representative of a second predetermined synchronization word and another transmission data signal which succeeds said frame synchronization signal, said second predetermined synchronization word being defined by inverting said first predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; and counting means connected to said first and said second synchronization word detecting means and having an initial value, an upper threshold value, and a lower threshold value, said upper threshold value being higher than said initial value by a preselected value M, where M represents a second integer greater than one, said lower threshold value being lower than said initial value by said preselected value, said counting means being for counting up and down a count in response to said first and said second detection pulses, respectively, to produce said first and said second judgement result signals when said count decreases down to said lower threshold value and when said count increases up to said upper threshold value, respectively.

Claim 5

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than two, the first frame of each multiframe comprising a multiframe synchronization signal representative of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal representative of a second predetermined synchronization word and another transmission data signal which succeeds said frame synchronization signal, said second predetermined synchronization word being defined by inverting said first predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; and counting means connected to said first and said second synchronization word detecting means and having an initial value, an upper threshold value, and a lower threshold value, said upper threshold value being higher than said initial value by a preselected value M, where M represents a second integer greater than one, said lower threshold value being lower than said initial value by said preselected value, said counting means being for counting up and down a count in response to said first and said second detection pulses, respectively, to produce said first and said second judgement result signals when said count decreases down to said lower threshold value and when said count increases up to said upper threshold value, respectively.

Claim 6

A polarity judging arrangement as claimed in claim 3, further comprising: count stopping means connected to said counting means for stopping said counting means in response to one of said first and said second judgement result signals to make said counting means continuously produce said one of the first and the second judgement result signals after reception of said one of the first and the second judgement result signals.

Claim 7

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than two, the first frame of each multiframe comprising a multiframe synchronization signal representative of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polartiy and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; and counting means connected to said first and said second synchronization word detecting means and having an initial value, an upper threshold value, and a lower threshold value, said upper threshold value being higher than said initial value by a preselected value M, where M represents a second integer greater than one, said lower threshold value being lower than said initial value by said preselected value, said counting means being for counting down and up a count in response to said first and said second detection pulses, respectively, to produce said first and said second judgement result signals when said count increases up to said upper threshold value and when said count decreases down to said lower threshold value, respectively.

Claim 8

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than two, the first frame of each multiframe comprising a multiframe synchronization signal representative of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polartiy and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; and counting means connected to said first and said second synchronization word detecting means and having an initial value, an upper threshold value, and a lower threshold value, said upper threshold value being higher than said initial value by a preselected value M, where M represents a second integer greater than one, said lower threshold value being lower than said initial value by said preselected value, said counting means being for counting down and up a count in response to said first and said second detection pulses, respectively, to produce said first and said second judgement result signals when said count increases up to said upper threshold value and when said count decreases down to said lower threshold value, respectively.

Claim 9

A polarity judging arrangement as claimed in claim 5, further comprising: count stopping means connected to said counting means for stopping said counting means in response to one of said first and said second judgement result signals to make said counting means continuously produce said one of the first and the second judgement result signals after reception of said one of the first and the second judgement result signals.

Claim 10

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than two, the first frame of each multiframe comprising a multiframe synchronization signal representative of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; and counting means connected to said first and said second synchronization word detecting means and having an initial value, an upper threshold value, and a lower threshold value, said upper threshold value being higher than said initial value by a preselected value M, where M represents a second integer greater than one, said lower threshold value being lower than said initial value by said preselected value, said counting means being for counting up and down a count in response to said first and said second detection pulses, respectively, to produce said first and said second judgement result signals when said count decreases down to said lower threshold value and when said count increases up to said upper threshold value, respectively.

Claim 11

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than two, the first frame of each multiframe comprising a multiframe synchronization signal representative of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; and counting means connected to said first and said second synchronization word detecting means and having an initial value, an upper threshold value, and a lower threshold value, said upper threshold value being higher than said initial value by a preselected value M, where M represents a second integer greater than one, said lower threshold value being lower than said initial value by said preselected value, said counting means being for counting up and down a count in response to said first and said second detection pulses, respectively, to produce said first and said second judgement result signals when said count decreases down to said lower threshold value and when said count increases up to said upper threshold value, respectively.

Claim 12

A polarity judging arrangement as claimed in claim 7, further comprising: count stopping means connected to said counting means for stopping said counting means in response to one of said first and said second judgement result signals to make said counting means continuously produce said one of the first and the second judgment result signals after reception of said one of the first and the second judgement result signals.

Claim 13

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than five, the first frame of each multiframe comprising a multiframe synchronization signal of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, the frame synchronization signal of at least one of said second through said N-th frames except said at least two of said second through said N-th frames of each multiframe representing a third predetermined synchronization word which is different from any one of said first and said second predetermined synchronization words, each of the frame synchronization signals of at least two remaining ones of said second through said N-th frames of each multiframe representing a fourth predetermined synchronization word defined by inverting said third predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; third synchronization word detecting means supplied with said received digital signal for detecting said third predetermined synchronization word to produce a third detection pulse whenever said third synchronization word detecting means detects said third predetermined synchronization word; fourth synchronization word detecting means supplied with said received digital signal for detecting said fourth predetermined synchronization word to produce a fourth detection pulse whenever said fourth synchronization word detecting means detects said fourth predetermined synchronization word; first counting means connected to said first and said second synchronization word detecting means and having a first initial value, a first upper threshold value, and a lower threshold value, said first upper threshold value being higher than said first initial value by a preselected value M, where M represents a second integer greater than one, said first lower threshold value being lower than said first initial value by said preselected value, said first counting means being for counting down and up a first count in response to said first and said second detection pulses, respectively, to produce first and second output signals when said first count increases up to said first upper threshold value and when said first count decreases down to said lower threshold value, respectively; first count stopping means connected to said first counting means for stopping said first counting means in response to one of said first and said second output signals to make said first counting means continuously produce said one of the first and the second output signals after reception of said one of the first and the second output signals; second counting means connected to said third and said fourth synchronization word detecting means and having a second initial value, a second upper threshold value, and a second lower threshold value, said second upper threshold value being higher than said second initial value by said preselected value, said second lower threshold value being lower than said second initial value by said preselected value, said second counting means being for counting down and up a second count in response to said third and said fourth detection pulses, respectively, to produce third and fourth output signals when said second count increases up to said second upper threshold value and when said second count decreases down to said lower threshold value, respectively; second count stopping means connected to said second counting means for stopping said second counting means in response to one of said third and said fourth output signals to make said second counting means continuously produce said one of the third and the fourth output signals after reception of said one of the third and the fourth output signals; and judgement result signal producing means connected to said first and said second counting means for producing said first and said second judgement result signals while said judgement result signal producing means receives said first and said third output signals and while said judgement result signal producing means receives said second and said fourth output signals, respectively.

Claim 14

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than five, the first frame of each multiframe comprising a multiframe synchronization signal of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, the frame synchronization signal of at least one of said second through said N-th frames except said at least two of said second through said N-th frames of each multiframe representing a third predetermined synchronization word which is different from any one of said first and said second predetermined synchronization words, each of the frame synchronization signals of at least two remaining ones of said second through said N-th frames of each multiframe representing a fourth predetermined synchronization word defined by inverting said third predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; third synchronization word detecting means supplied with said received digital signal for detecting said third predetermined synchronization word to produce a third detection pulse whenever said third synchronization word detecting means detects said third predetermined synchronization word; fourth synchronization word detecting means supplied with said received digital signal for detecting said fourth predetermined synchronization word to produce a fourth detection pulse whenever said fourth synchronization word detecting means detects said fourth predetermined synchronization word; first counting means connected to said first and said second synchronization word detecting means and having a first initial value, a first upper threshold value, and a lower threshold value, said first upper threshold value being higher than said first initial value by a preselected value M, where M represents a second integer greater than one, said first lower threshold value being lower than said first initial value by said preselected value, said first counting means being for counting down and up a first count in response to said first and said second detection pulses, respectively, to produce first and second output signals when said first count increases up to said first upper threshold value and when said first count decreases down to said lower threshold value, respectively; first count stopping means connected to said first counting means for stopping said first counting means in response to one of said first and said second output signals to make said first counting means continuously produce said one of the first and the second output signals after reception of said one of the first and the second output signals; second counting means connected to said third and said fourth synchronization word detecting means and having a second initial value, a second upper threshold value, and a second lower threshold value, said second upper threshold value being higher than said second initial value by said preselected value, said second lower threshold value being lower than said second initial value by said preselected value, said second counting means being for counting down and up a second count in response to said third and said fourth detection pulses, respectively, to produce third and fourth output signals when said second count increases up to said second upper threshold value and when said second count decreases down to said lower threshold value, respectively; second count stopping means connected to said second counting means for stopping said second counting means in response to one of said third and said fourth output signals to make said second counting means continuously produce said one of the third and the fourth output signals after reception of said one of the third and the fourth output signals; and judgement result signal producing means connected to said first and said second counting means for producing said first and said second judgement result signals while said judgement result signal producing means receives said first and said third output signals and while said judgement result signal producing means receives said second and said fourth output signals, respectively.

Claim 15

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than five, the first frame of each multiframe comprising a multiframe synchronization signal of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, the frame synchronization signal of at least one of said second through said N-th frames except said at least two of said second through said N-th frames of each multiframe representing a third predetermined synchronization word which is different from any one of said first and said second predetermined synchronization words, each of the frame synchronization signals of at least two remaining ones of said second through said N-th frames of each multiframe representing a fourth predetermined synchronization word defined by inverting said third predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; third synchronization word detecting means supplied with said received digital signal for detecting said third predetermined synchronization word to produce a third detection pulse whenever said third synchronization word detecting means detects said third predetermined synchronization word; fourth synchronization word detecting means supplied with said received digital signal for detecting said fourth predetermined synchronization word to produce a fourth detection pulse whenever said fourth synchronization word detecting means detects said fourth predetermined synchronization word; first counting means connected to said first and said second synchronization word detecting means and having a first initial value, a first upper threshold value, and a lower threshold value, said first upper threshold value being higher than said first initial value by a preselected value M, where M represents a second integer greater than one, said first lower threshold value being lower than said first initial value by said preselected value, said first counting means being for counting up and down a first count in response to said first and said second detection pulses, respectively, to produce first and second output signals when said first count decreases down to said first lower threshold value and when said first count increases up to said upper threshold value, respectively; first count stopping means connected to said first counting means for stopping said first counting means in response to one of said first and said second output signals to make said first counting means continuously produce said one of the first and the second output signals after reception of said one of the first and the second output signals; second counting means connected to said third and said fourth synchronization word detecting means and having a second initial value, a second upper threshold value, and a second lower threshold value, said second upper threshold value being higher than said second initial value by said preselected value, said second lower threshold value being lower than said second initial value by said preselected value, said second counting means being for counting up and down a second count in response to said third and said fourth detection pulses, respectively, to produce third and fourth output signals when said second count decreases down to said second lower threshold value and when said second count increases up to said upper threshold value, respectively; second count stopping means connected to said second counting means for stopping said second counting means in response to one of said third and said fourth output signals to make said second counting means continuously produce said one of the third and the fourth output signals after reception of said one of the third and the fourth output signals; and judgement result signal producing means connected to said first and said second counting means for producing said first and said second judgement result signals while said producing means receives said first and said third output signals and while said producing means receives said second and said fourth output signals, respectively.

Claim 16

A polarity judging arrangement for use in a reception section of a digital transmission network comprising a transmission section and a transmission line between said transmission and said reception sections, said transmission section transmitting to said transmission line a time division multiplexed digital signal comprising successive multiframes, each comprising first, second, . . . , and N-th frames, where N represents a first integer greater than five, the first frame of each multiframe comprising a multiframe synchronization signal of a first predetermined synchronization word and a transmission data signal which succeeds said multiframe synchronization signal, each of said second through said N-th frames of each multiframe comprising a frame synchronization signal and another transmission data signal which succeeds said frame synchronization signal, each of the frame synchronization signals of at least two of said second through said N-th frames of each multiframe representing a second predetermined synchronization word defined by inverting said first predetermined synchronization word, the frame synchronization signal of at least one of said second through said N-th frames except said at least two of said second through said N-th frames of each multiframe representing a third predetermined synchronization word which is different from any one of said first and said second predetermined synchronization words, each of the frame synchronization signals of at least two remaining ones of said second through said N-th frames of each multiframe representing a fourth predetermined synchronization word defined by inverting said third predetermined synchronization word, said reception section receiving, as a received digital signal, said time division multiplexed digital signal from said transmission line, said received digital signal having a true polarity equivalent to a polarity of said time division multiplexed digital signal when said transmission line is correctly connected in polarity between said transmission and said reception sections, said received digital signal having an inverted polarity relative to said true polarity when said transmission line is incorrectly connected in polarity between said transmission and said reception sections, said polarity judging arrangement being for judging whether said received digital signal has said true polarity or said inverted polarity, said polarity judging arrangement thereby producing first and second judgement result signals when said polarity judging arrangement judges that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said first and said second judgement result signals representing that said received digital signal has said true polarity and that said received digital signal has said inverted polarity, respectively, said polarity judging arrangement comprising: first synchronization word detecting means supplied with said received digital signal for detecting said first predetermined synchronization word to produce a first detection pulse whenever said first synchronization word detecting means detects said first predetermined synchronization word; second synchronization word detecting means supplied with said received digital signal for detecting said second predetermined synchronization word to produce a second detection pulse whenever said second synchronization word detecting means detects said second predetermined synchronization word; third synchronization word detecting means supplied with said received digital signal for detecting said third predetermined synchronization word to produce a third detection pulse whenever said third synchronization word detecting means detects said third predetermined synchronization word; fourth synchronization word detecting means supplied with said received digital signal for detecting said fourth predetermined synchronization word to produce a fourth detection pulse whenever said fourth synchronization word detecting means detects said fourth predetermined synchronization word; first counting means connected to said first and said second synchronization word detecting means and having a first initial value, a first upper threshold value, and a lower threshold value, said first upper threshold value being higher than said first initial value by a preselected value M, where M represents a second integer greater than one, said first lower threshold value being lower than said first initial value by said preselected value, said first counting means being for counting up and down a first count in response to said first and said second detection pulses, respectively, to produce first and second output signals when said first count decreases down to said first lower threshold value and when said first count increases up to said upper threshold value, respectively; first count stopping means connected to said first counting means for stopping said first counting means in response to one of said first and said second output signals to make said first counting means continuously produce said one of the first and the second output signals after reception of said one of the first and the second output signals; second counting means connected to said third and said fourth synchronization word detecting means and having a second initial value, a second upper threshold value, and a second lower threshold value, said second upper threshold value being higher than said second initial value by said preselected value, said second lower threshold value being lower than said second initial value by said preselected value, said second counting means being for counting up and down a second count in response to said third and said fourth detection pulses, respectively, to produce third and fourth output signals when said second count decreases down to said second lower threshold value and when said second count increases up to said upper threshold value, respectively; second count stopping means connected to said second counting means for stopping said second counting means in response to one of said third and said fourth output signals to make said second counting means continuously produce said one of the third and the fourth output signals after reception of said one of the third and the fourth output signals; and judgement result signal producing means connected to said first and said second counting means for producing said first and said second judgement result signals while said producing means receives said first and said third output signals and while said producing means receives said second and said fourth output signals, respectively.