Method for bidirectionally transmitting digital video signal and digital video signal bidirectionally transmitting system

Claim 2

A video signal transmission method as claimed in Claim 1, wherein said method further includes the steps of: dividing the second digital signal of said second video appliance in a plurality of predetermined periods, and time-axis compressing said second divided digital signal to produce said transmission signal repeating said signal period and said no signal period alternately; controlling said first and second video appliances so that said second compressed digital signal of said second video appliance is transmitted to said first video appliance in said second transmission period of said transmission path; receiving said second compressed digital signal from said second video appliance at said first video appliance; and time-axis expanding said received and second compressed digital signal to reproduce the original digital signal at the first video appliance.

Claim 3

A video signal transmission method as claimed in Claim 1, wherein said first digital signal is a time-divisional multiplexing at least a digital video signal and a digital audio signal.

Claim 4

A video signal transmission method as claimed in Claim 1, wherein time periods of said transmission period and said no transmission period are set to be different from each other.

Claim 5

A video signal transmission method as claimed in Claim 1 wherein: after said first transmission period transmitted the digital signal from said first video appliance (1, 2) has been ended, said second transmission period transmitted the digital signal from said second video appliance (1, 2) is commenced; and after said second transmission period transmitted the digital signal from said second video appliance (1, 2) has been ended, said first transmission period transmitted the digital signal from said first video appliance (1, 2) is commenced.

Claim 6

A video signal transmission method as claimed in Claim 1, wherein, after a predetermined delay time elapses since the digital signal transmitted in said signal period from said first video appliance has been ended, said second transmission period transmitted the digital signal from said second video appliance is commenced.

Claim 7

A video signal transmission method as claimed in Claim 6 wherein said predetermined delay time is set to be longer than a transmission delay time of the digital signal appearing in said transmission path.

Claim 8

A video signal transmission method as claimed in Claim 1, wherein in the step for dividing the digital signal a period of said video signal for one picture image is divided into a plurality of transferring periods, said transferring period includes said transmission period corresponding to each divided signal block and said no transmission period adjacent to said transmission period, and wherein in at least either one of said video appliances, said method further comprises a step for adding a signal representing a predetermined period phase of said video signal into a predetermined position of the time-axis compressed transmission signal at each period corresponding to positive integer times a unit period which is said period of said video signal for one picture image, and wherein in at least the other one of said video appliances, said method further comprising a step for detecting a signal representing a predetermined period phase of said video signal from the transmission signal transmitted from the opposite video appliance via the transmission path and a step for making synchronization of the predetermined period phase of the video signal as a reference of processing of the other one of said video appliances on the basis of the detected signal representing a predetermined period phase of said video signal.

Claim 9

A video signal transmission method as claimed in Claim 3, wherein in the step for dividing the digital signal a period of said video signal for one screen image is divided into a plurality of transferring periods, said transferring period includes said transmission period corresponding to each divided signal block and said no transmission period adjacent to said transmission period, and wherein in at least either one of said video appliances, said method further comprises a step for adding a signal representing a predetermined period phase of said video signal into a predetermined position of the time-axis compressed transmission signal at each period corresponding to positive integer times a unit period which is said period of said video signal for one picture image, and wherein in the other one of said video appliances, said method further comprising a step for detecting a signal representing a predetermined period phase of said video signal from the transmission signal transmitted from the opposite video appliance via the transmission path and a step for making synchronization of the predetermined period phase of the video signal as a reference of video processing on the basis of the detected signal representing a predetermined period phase of said video signal.

Claim 10

A video signal transmission method as claimed in Claim 8 wherein: when the predetermined period of said video signal is Tf, said transferring period is a value selected from one of the following equations: (a) Tf = n × Tn, (b) Tf = n × Tn + m × Tm, (c) Tf = n × Tn + m × Tm + K × Tk, and (d) Tf = Σ(ni × Ti), where symbols Tn, Tm, Tk, Ti denote said transferring period, and symbols n, m, k, ni, i represent positive integers other than 0.

Claim 11

A video signal transmission method as claimed in Claim 10 wherein the predetermined period Tf of said video signal is set to a period corresponding to a 1 frame period of said video signal multiplied by any positive integers other than 0, and said signal representing the predetermined period phase of the video signal corresponds to a signal synchronized with said period phase of said 1 frame multiplied by said integers.

Claim 12

A video signal transmission method as claimed in Claim 10 wherein the predetermined period Tf of said video signal is set to a period corresponding to a 1 field period of said video signal multiplied by any positive integers other than 0, and said signal representing the predetermined period phase of the video signal corresponds to a signal synchronized with said period phase of said 1 field multiplied by said integers.

Claim 13

A video signal transmission method as claimed in Claim 1 wherein at least one of said video appliances (1, 2) further comprises a step for data-compressing said digital signal.

Claim 14

A video signal transmission method as claimed in Claim 8, wherein at least one of said appliances, said method further comprising a step for adding a synchronization signal in a predetermined position of the transmission signal at each transmission period, and wherein in at least either one of said video appliances, said method further comprising a step for detecting said synchronization signal from the transmission signal transmitted from opposite video appliance via the transmission path, and a step for stopping the transmission of the signal during a predetermined time in a case of no detection of said synchronization signal in a predetermined detection repetition pattern within at least a predetermined time.

Claim 15

A video signal transmission method as claimed in Claim 8, wherein in at least one of said appliances, said method further comprising a step for adding a synchronization signal in a predetermined position of the transmission signal at least transmission period, and wherein in at least either one of said video appliances, said method further comprising a step for detecting said synchronization signal from the transmission signal transmitted from opposite video appliance via the transmission path, and a step for stopping the transmission of the signal during a predetermined time in a case of no detection of said synchronization signal in a predetermined detection repetition pattern within at least a predetermined time.

Claim 16

A video signal transmission method as claimed in Claim 1 wherein: at each of said video appliances (1, 2) further comprises a step for transmitting a signal having a level substantially equal to an average value of said digital signals of said transmission period during said no transmission period.

Claim 17

A video signal transmission method as claimed in Claim 16, further comprising a step of discriminating a high level and a low level based on a predetermined reference value from said received digital signal, wherein said reference value is set to such a value which is lower than an average value of said digital signals by a value corresponding to an attenuation amount of the digital signal in said transmission path.

Claim 18

In a video signal transmission system wherein digital signals containing at least digital video signals and digital audio signals are bidirectionally transmitted and received in a substantially real time in first and second video appliances (1, 2) coupled via a transmission path (7) to each other, said first video appliance (1, 2) characterized by: means (5-1, 5-2, 102, 115) for producing digital signal by time-divisional multiplexing of at least said digital video signal and said digital audio signal; means (5-1, 5-2, 103, 112) for dividing said digital signal in a plurality of predetermined period and time-axis compressing said divided signals in order to produce a transmission signal repeating a signal period and a no signal period alternately; means (6-1, 6-2, 120, 122) for controlling said first and second video appliances to generate a first transmission period and a second transmission period alternately in said transmission path, so that said first compressed digital signal of said first video appliance in said signal period is transmitted to said second video appliance in said first period of said transmission path; means (6-1, 6-2, 119, 121) for receiving said first compressed digital signal from said first video appliance at said second video appliance; means (8-1, 8-2, 106, 114) for time-axis expanding said received and first compressed digital signal to reproduce the original digital signal at said second video appliance; and means (8-1, 8-2, 105, 116) for time-divisional separating said time-axis expanded digital signal to reproduce at least the original digital video signal and the digital audio signal.

Claim 19

A video signal transmission system as claimed in Claim 18, wherein said first and second appliances includes: means for producing a digital signal by time-divisional multiplexing at least said digital video signal and said digital audio signal; means for time-divisional separating said time-axis expanded digital signal to reproduce at least the original digital video signal and the digital audio signal; said means (5-1, 5-2, 102, 112) for producing a transmission signal is means for dividing said video signal period forming one picture image into a plurality of transferring period and for time-axis compressing each of divided signal blocks and for producing a transmission signal which repeats said transmission period corresponding to each of divided signal blocks and said no transmission period adjacent to said transmission period; said first video appliance further comprising means for adding a signal representing a preselected period phase of said video signal into a predetermined position of the time-axis compressed transmission signal at each period corresponding to positive integer (except for zero) times a unit period which is said period of video signal for one screen image; and said second video appliances further comprising means for detecting a signal representing a predetermined period phase of said video signal from the transmission signal transmitted from the first video appliance via the transmission path at each predetermined period of said video signal and means for making synchronization of the predetermined period phase of the video signal as a reference of video processing on the basis of the detected signal representing a predetermined period phase of said video signal.

Claim 20

A video signal transmission system as claimed in Claim 19, wherein at least one of said first and second appliances comprises means for adding a synchronization signal in a predetermined position of the transmission at each transmission period, and at least the other one of said first and second video appliances further comprises means for detecting said synchronization signal from the transmission signal transmitted from opposite video appliance via the transmission path, and means for stopping the transmission of the signal in a predetermined time in said transmission period in a case of no detection of said synchronization signal in a predetermined detection repetition pattern within a predetermined time.

Claim 21

A video signal transmission system as claimed in Claim 18 wherein at least one of said first and second video appliances (1, 2) further comprises means for data-compressing said digital signal.

Claim 22

A video signal transmission system as claimed in Claim 21 wherein one of said first and second video appliances is a television camera (1), and the other of said first and second video appliances is a television camera controlling apparatus (2).

Claim 23

A video signal transmission system as claimed in Claim 22 wherein said first video appliance is a television camera controlling apparatus (2), and said second video appliance is a television camera (1).

Claim 24

A video signal transmission system as claimed in Claim 18 wherein said transmission path contains a triple coaxial cable.