Patent US5185679A successfully refreshed from Google Patents.
US5185679A
Expired / Lapsed
US
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Inversion phenomenon preventing circuit
Assignee: Mitsubishi Electric Corp
•
Filing: 1989-05-11
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Granted: 1993-02-09
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Expires: 2009-05-11
Abstract
Abstract An FM signal which is partly missing zero crossing points is supplied to an input terminal, to which a second polarity discriminating circuit and a lower side band suppressing circuit followed by a first polarity discriminating circuit are coupled together. A pulse extracting circuit receives the outputs of the first polarity discriminating circuit and a second polarity discriminating circuit to produce pulses corresponding only to portions of the FM signal at which the zero crossing points are absent. The pulses thus obtained are subsequently combined in a waveform reforming circuits with the FM signal from the input terminal, thereby permitting the FM signal to regain the zero crossing points.
Inventors
- 👤 Hidetoshi Mishima
- 👤 Keiji Hatanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:17
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/93
Claims Analysis
Total Claims: 112
Claim 1
Independent Claim
257 words
An apparatus for preventing inversion phenomenon resulting from drop out of at least one zero crossing point, comprising: an input terminal for receiving a recovered frequency modulated signal having at least one missing zero crossing point pair; lower side band attenuator connected to said terminal and producing an output of the recovered frequency modulated signal with an attenuated lower side band; first polarity discriminating means, connected to the output of said lower side band attenuator, for outputting a signal indicative of each of positive and negative amplitudes of the output of said lower side band attenuator; second polarity discriminating means connected to said input terminal, said second polarity discriminating means outputting a signal indicative of each of said positive and negative amplitudes of said frequency modulated signal; pulse extracting means for taking a difference between the output from said first polarity discriminating means and the output of said second polarity discriminating means to produce a difference signal, and for extracting a single discrete signal component of said difference signal, having width greater than a predetermined value, from said difference signal only for each missing zero crossing point pair to produce only a single pulse having pulse width corresponding to said single discrete signal component for each missing zero crossing point pair; waveform reforming means, responsive to each said single pulse developed by said pulse extraction means and to said recovered frequency modulated signal, for adding only said single pulses to said recovered frequency modulated signal to recover said zero crossing points missing from said frequency modulated signal.
Claim 2
Independent Claim
257 words
An apparatus for preventing inversion phenomenon resulting from drop out of at least one zero crossing point, comprising: an input terminal for receiving a recovered frequency modulated signal having at least one missing zero crossing point pair; lower side band attenuator connected to said terminal and producing an output of the recovered frequency modulated signal with an attenuated lower side band; first polarity discriminating means, connected to the output of said lower side band attenuator, for outputting a signal indicative of each of positive and negative amplitudes of the output of said lower side band attenuator; second polarity discriminating means connected to said input terminal, said second polarity discriminating means outputting a signal indicative of each of said positive and negative amplitudes of said frequency modulated signal; pulse extracting means for taking a difference between the output from said first polarity discriminating means and the output of said second polarity discriminating means to produce a difference signal, and for extracting a single discrete signal component of said difference signal, having width greater than a predetermined value, from said difference signal only for each missing zero crossing point pair to produce only a single pulse having pulse width corresponding to said single discrete signal component for each missing zero crossing point pair; waveform reforming means, responsive to each said single pulse developed by said pulse extraction means and to said recovered frequency modulated signal, for adding only said single pulses to said recovered frequency modulated signal to recover said zero crossing points missing from said frequency modulated signal.
Claim 3
Dependent Claim
45 words
An inversion phenomenon preventing apparatus according to claim 1, further comprising signal processing means for processing said recovered frequency modulated signal prior to providing it to said waveform reforming means, said processing being selected from one or more of amplitude limiting, equalizing, and signal delaying.
Claim 4
Dependent Claim
56 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said pulse extracting means includes integration means for integrating said pulses to produce signals having amplitudes substantially proportional to pulse widths of said pulses; said waveform reforming means including a comparator having a threshold level which varies in accordance with said signal produced by intergration means.
Claim 5
Dependent Claim
23 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said waveform reforming means includes a limiter for amplitude limiting the output thereof.
Claim 6
Dependent Claim
20 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said lower side band attenuator is a high pass filter.
Claim 7
Dependent Claim
19 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said lower side band attenuator is a sine filter.
Claim 8
Dependent Claim
20 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said lower side band attenuator is a band pass filter.
Claim 9
Dependent Claim
19 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said first and second polarity discriminating means include comparators.
Claim 10
Dependent Claim
20 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said first and second polarity discriminating means include amplitude limiters.
Claim 11
Dependent Claim
20 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said waveform reforming means is a two-input exclusive OR circuit.
Claim 12
Dependent Claim
46 words
An inversion phenomenon preventing apparatus according to claim 10, wherein said pulse extracting means comprises a two-input exclusive OR circuit, a low pass filter connected to the output of said two-input exclusive OR circuit, and a comparator connected to the output of said low pass filter.
Claim 13
Dependent Claim
64 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said pulse extracting means comprises a two-input exclusive OR circuit, a delay circuit connected to the output of said two-input exclusive OR circuit having, and a two-input AND circuit one input of thereof connected to the output of said delay circuit and the other input thereof connected to the input of said delay circuit.
Claim 14
Dependent Claim
100 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said apparatus further comprises: polarity control means, connected to the output of said pulse extracting means, for converting said pulses produced by from said pulse extracting means into second pulses having polarity depending on the polarity of the output of said second polarity discriminating means and said pulses, said polarity control means outputting said second pulses to said waveform reforming means; wherein said waveform reforming means reconstructs said zero crossing points partly absent in said FM signal from said frequency modulated signal and the output of said polarity control means.
Claim 15
Dependent Claim
36 words
An inversion phenomenon preventing apparatus according to claim 13, wherein said apparatus further comprises a delay circuit; said frequency modulated signal being supplied to said waveform reforming means from said input terminal through said delay circuit.
Claim 16
Dependent Claim
55 words
An inversion phenomenon preventing apparatus according to claim 13, wherein said apparatus further comprises a delay circuit connected to said input terminal and a limiter connected to the output of said delay circuit; said frequency modulated signal being supplied to said waveform reforming means from said input terminal through said delay circuit and said limiter.
Claim 17
Dependent Claim
55 words
An inversion phenomenon preventing apparatus according to claim 13, wherein said apparatus further comprises a delay circuit connected to said input terminal, and an equalizer connected to the output of said delay circuit; said frequency modulated signal being supplied to said waveform reforming means from said input terminal through said delay circuit and said equalizer.
Claim 18
Dependent Claim
17 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said waveform reforming means includes an adder.
Claim 19
Dependent Claim
40 words
An inversion phenomenon preventing apparatus according to claim 17, wherein said pulse extracting means comprises a subtracter, a low pass filter connected to the output of said subtracter, and a slicer connected to the output of said low pass filter.
Claim 20
Dependent Claim
36 words
An inversion phenomenon preventing apparatus according to claim 18, wherein said apparatus further comprises a delay circuit; said frequency modulated signal being supplied to said waveform reforming means from said input terminal through said delay circuit.
Claim 21
Dependent Claim
66 words
An inversion phenomenon preventing apparatus according to claim 18, wherein said apparatus further comprises an equalizer connected to said input terminal, a delay circuit connected to the output of said equalizer, and a limiter connected to the output of said delay circuit; said frequency modulated signal being supplied to said waveform reforming means from said input terminal through said equalizer, said delay circuit, and said limiter.
Claim 22
Dependent Claim
46 words
An inversion phenomenon preventing apparatus according to claim 18 wherein said apparatus further comprises an equalizer and a delay circuit connected to the output of said equalizer, said frequency modulated signal being supplied to said waveform reforming means from said input terminal through said delay circuit.
Claim 23
Dependent Claim
31 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said recovered frequency modulated signal is missing said at least one missing zero crossing point pair when output from a tape.
Claim 24
Dependent Claim
32 words
An inversion phenomenon preventing apparatus according to claim 1, wherein said recovered frequency modulated signal is missing said at least one missing zero crossing point pair when output from a frequency equalizer.
Claim 25
Independent Claim
125 words
A system for preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from drop out of at least one zero crossing point, wherein one or more pairs of zero crossing points are missing, comprising: means for identifying only the pairs of missing zero crossing points of the recovered frequency modulated signal and producing a missing zero crossing point identifying signal describing only missing zero crossing point pairs; means, responsive to the missing zero crossing point identifying signal, for producing only a single individual pulse associated with each identified missing zero crossing point pair; and means for combining each said individual pulse, developed by said means for producing only a single individual pulse, with the recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 26
Independent Claim
125 words
A system for preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from drop out of at least one zero crossing point, wherein one or more pairs of zero crossing points are missing, comprising: means for identifying only the pairs of missing zero crossing points of the recovered frequency modulated signal and producing a missing zero crossing point identifying signal describing only missing zero crossing point pairs; means, responsive to the missing zero crossing point identifying signal, for producing only a single individual pulse associated with each identified missing zero crossing point pair; and means for combining each said individual pulse, developed by said means for producing only a single individual pulse, with the recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 27
Dependent Claim
27 words
The system of claim 24 wherein said means for combining combines only individual pulses associated with missing zero crossing point pairs with said recovered frequency modulated signal.
Claim 28
Dependent Claim
23 words
The system of claim 24 wherein said means for identifying performs additions and subtractions to produce the missing zero crossing point identifying signal.
Claim 29
Dependent Claim
23 words
The system of claim 24 wherein said means for identifying performs boolean algebraic operations to produce the missing zero crossing point identifying signal.
Claim 30
Dependent Claim
28 words
The system of claim 24 wherein said means for identifying includes a filter removing low frequencies from said recovered frequency modulated signal to recreate missing zero crossing points.
Claim 31
Dependent Claim
17 words
The system of claim 28 wherein said filter is a high pass filter exhibiting good phase linearity.
Claim 32
Dependent Claim
13 words
The system of claim 28 wherein said filter is a band pass filter.
Claim 33
Dependent Claim
12 words
The system of claim 28 wherein said filter is a sine filter.
Claim 34
Dependent Claim
53 words
The system of claim 28 wherein said means for identifying further includes difference means, responsive to the filtered recovered frequency modulated signal, for taking a difference between the filtered frequency modulated signal and said recovered frequency modulated signal to extract a missing zero crossing point identifying signal containing the missing zero crossing points.
Claim 35
Dependent Claim
17 words
The system of claim 32 wherein said means for taking a difference includes an adder or subtractor.
Claim 36
Dependent Claim
17 words
The system of claim 32 wherein said means for taking a difference includes an exclusive OR gate.
Claim 37
Dependent Claim
61 words
The system of claim 32 wherein said means for producing at least one individual pulse includes, a low pass filter receiving and filtering said missing zero crossing point identifying signal, and a slicer slicing a portion of said filtered missing zero crossing point identifying signal around each missing zero crossing point pair to form at least one phase corrected compensation pulse.
Claim 38
Dependent Claim
23 words
The system of claim 35 wherein said low pass filter attenuates phase shift causing high frequency components from said recovered frequency modulated portion.
Claim 39
Dependent Claim
34 words
The system of claim 35 wherein said low pass filter reduces the amplitude of differences between the filtered frequency modulated signal and said recovered frequency modulated signal not associated with missing zero crossing points.
Claim 40
Dependent Claim
85 words
The system of claim 32 wherein said means for producing only a single individual pulse includes, a delay receiving and delaying said missing zero crossing point identifying signal, and an AND gate receiving said missing zero crossing point identifying signal and said delayed missing zero crossing point identifying signal received from said delay; said difference means defining only missing zero crossing points in said missing zero crossing point identifying signal, to remove phase shift producing short duration pulses, unrelated to missing zero crossing points, therefrom.
Claim 41
Dependent Claim
69 words
The system of claim 32 wherein said means for producing only a single individual pulse includes, a low pass filter receiving and filtering said missing zero crossing point identifying signal, and a comparator comparing said filtered missing zero crossing point identifying signal with a threshold, to remove phase shift producing short duration pulses unrelated to missing zero crossing points therefrom, to form at least one phase corrected compensation pulse.
Claim 42
Dependent Claim
26 words
The system of claim 32 wherein said means for identifying further includes compensation means for compensating for the phase shift caused by said high pass filter.
Claim 43
Dependent Claim
14 words
The system of claim 40 wherein said means for compensating includes a phase equalizer.
Claim 44
Dependent Claim
21 words
The system of claim 40 wherein said means for compensating includes a first delay for delaying said recovered frequency modulated signal.
Claim 45
Dependent Claim
52 words
The system of claim 32 wherein said means for identifying further includes, a first limiter for limiting the recovered frequency modulated signal to produce a limited recovered frequency modulated signal, and a second limiter for limiting the filtered recovered frequency modulated signal to produce a filtered and limited recovered frequency modulated signal.
Claim 46
Dependent Claim
59 words
The system of claim 32 wherein said means for identifying further includes, a first comparator for comparing the recovered frequency modulated signal with a predetermined threshold to produce a limited recovered frequency modulated signal, and a second comparator comparing the filtered recovered frequency modulated signal to a predetermined threshold to produce a filtered and limited recovered frequency modulated signal.
Claim 47
Dependent Claim
41 words
The system of claim 24 wherein said means for combining includes an adder for adding said individual pulses produced by said means for producing to said recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 48
Dependent Claim
43 words
The system of claim 24 wherein said means for combining includes an exclusive OR gate for combining said individual pulses produced by said means for producing with said recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 49
Dependent Claim
45 words
The system of claim 24 wherein said means for combining includes a comparator receiving said recovered frequency modulated signal, said comparator comparing said recovered frequency modulated signal with said at least one individual pulse to produce a missing zero crossing point corrected frequency modulated signal.
Claim 50
Dependent Claim
22 words
The system of claim 44 wherein said first and second comparators are polarity discrimination circuits and said predetermined thresholds are zero volts.
Claim 51
Dependent Claim
50 words
The system of claim 48 further comprising polarity control circuit, responsive to said first comparator, for selectively inverting said individual pulses to make their polarity subtractive from said recovered frequency modulated signal to thereby add missing zero crossing points to produce a missing zero crossing point corrected frequency modulated signal.
Claim 52
Dependent Claim
27 words
The system of claim 24, wherein said recovered frequency modulated signal is missing said one or more pairs of zero crossing points when output from a tape.
Claim 53
Dependent Claim
28 words
The system of claim 24, wherein said recovered frequency modulated signal is missing said one or more pairs of zero crossing points when output from a frequency equalizer.
Claim 54
Independent Claim
96 words
A method of preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising the steps of: (a) identifying only pairs of missing zero crossing points of the recovered frequency modulated signal; (b) producing only a single individual pulse for each missing zero crossing point pair identified in said step (a); and (c) combining said single pulses developed by said step (b) with the recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 55
Independent Claim
96 words
A method of preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising the steps of: (a) identifying only pairs of missing zero crossing points of the recovered frequency modulated signal; (b) producing only a single individual pulse for each missing zero crossing point pair identified in said step (a); and (c) combining said single pulses developed by said step (b) with the recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 56
Dependent Claim
23 words
The method of claim 52 wherein only individual pulses associated with missing zero crossing points are combined with the recovered frequency modulated signal.
Claim 57
Dependent Claim
21 words
The method of claim 52 wherein said step (a) performs additions and subtractions to produce a missing zero crossing point signal.
Claim 58
Dependent Claim
21 words
The method of claim 52 wherein said step (a) performs boolean algebraic operations to produce a missing zero crossing point signal.
Claim 59
Dependent Claim
38 words
The method of claim 52 wherein said step (a) includes the step of (i) suppressing the lower side band of the recovered frequency modulated signal to produce a filtered frequency modulated signal to recover all zero crossing points.
Claim 60
Dependent Claim
33 words
The method of claim 52 wherein said at least one pulse produced by said step (b) simulates the originally generated frequency modulated signal in the area about the missing zero crossing point locations.
Claim 61
Dependent Claim
47 words
The method of claim 56 wherein said step (a) further includes the step of (ii) taking a difference between the filtered frequency modulated signal and the recovered frequency modulated signal to extract a missing zero crossing point identifying signal associated with each missing zero crossing point pair.
Claim 62
Dependent Claim
15 words
The method of claim 58 wherein said step (ii) is performed by adding or subtracting.
Claim 63
Dependent Claim
21 words
The method of claim 58 wherein said step of taking a difference is performed by performing a Boolean exclusive OR operation.
Claim 64
Dependent Claim
52 words
The method of claim 58 wherein said step (b) includes the steps of, (i) filtering the missing zero crossing point identifying signal, and (ii) slicing a portion of the filtered missing zero crossing point identifying signal around each missing zero crossing point pair to form at least one phase corrected compensation pulse.
Claim 65
Dependent Claim
22 words
The method of claim 61 wherein said step (i) attenuates phase shift cuasing high frequency components from the recovered frequency modulated portion.
Claim 66
Dependent Claim
33 words
The method of claim 61 wherein said step (i) reduces the amplitude of differences between the filtered frequency modulated signal and the recovered frequency modulated signal not associated with missing zero crossing points.
Claim 67
Dependent Claim
76 words
The method of claim 58 wherein said step (b) includes the steps of, (i) delaying the missing zero crossing point signal, and (ii) logically ANDing the missing zero crossing point signal and the delayed missing zero crossing point signal of said step (i); said step (b) isolating pulses defining missing zero crossing points in the missing zero crossing point identifying signal to remove phase shift producing short duration pulses, unrelated to missing zero crossing points, therefrom.
Claim 68
Dependent Claim
60 words
The method of claim 58 wherein said step (b) includes the steps of, (i) filtering the missing zero crossing point identifying signal, and (ii) comparing the filtered missing zero crossing point identifying signal with a threshold to remove phase shift producing short duration pulses, unrelated to missing zero crossing points, therefrom, to form at least one phase corrected compensation pulse.
Claim 69
Dependent Claim
25 words
The method of claim 58 wherein said step (a) further includes the step of (iii) compensating for the phase shift caused by said step (i).
Claim 70
Dependent Claim
48 words
The method of claim 58 wherein said step (a) further includes the steps of, iv) limiting the recovered frequency modulated signal to produce a limited recovered frequency modulated signal, and v) limiting the filtered recovered frequency modulated signal to produce a filtered and limited recovered frequency modulated signal.
Claim 71
Dependent Claim
56 words
The method of claim 58 wherein said step (a) further includes the steps of, iv) comparing the recovered frequency modulated signal with a predetermined threshold to produce a limited recovered frequency modulated signal, and v) comparing the filtered recovered frequency modulated signal to a predetermined threshold to produce a filtered and limited recovered frequency modulated signal.
Claim 72
Dependent Claim
42 words
The method of claim 52 wherein said step (c) includes the step of (i) adding the individual pulses produced by said step (b) of producing to said recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 73
Dependent Claim
47 words
The method of claim 52 wherein said step (c) includes the step of (i) performing a logical exclusive OR operation to combine the individual pulses produced by said step (b) with the recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 74
Dependent Claim
37 words
The method of claim 52 wherein said step (c) includes the step of (i) comparing the recovered frequency modulated signal with at least one individual pulse to produce a missing zero crossing point corrected frequency modulated signal.
Claim 75
Dependent Claim
20 words
The method of claim 68 wherein said steps (iv) and (v) perform polarity discrimination using predetermined thresholds of zero volts.
Claim 76
Dependent Claim
45 words
The method of claim 72 further comprising the step of (d) selectively inverting the individual pulses to make their polarity subtractive from the recovered frequency modulated signal to thereby add missing zero crossing points to produce a missing zero crossing point corrected frequency modulated signal.
Claim 77
Dependent Claim
27 words
The method of claim 52, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a tape.
Claim 78
Dependent Claim
28 words
The method of claim 52, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a frequency equalizer.
Claim 79
Independent Claim
144 words
A system for preventing an inversion phenomena in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising: a filter suppressing the lower side band of the recovered frequency modulated signal to identify all zero crossing points and producing a filtered recovered frequency modulated signal; means, responsive to the filtered recovered frequency modulated signal, for producing a missing zero crossing point signal containing the missing zero crossing points; deletion means, responsive to said missing zero crossing point signal, for eliminating all portions of said recovered frequency modulated signal not associated with missing zero crossing points to produce a compensation pulse representing only missing zero crossing point pairs; and means for combining said compensation pulse with said recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 80
Independent Claim
144 words
A system for preventing an inversion phenomena in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising: a filter suppressing the lower side band of the recovered frequency modulated signal to identify all zero crossing points and producing a filtered recovered frequency modulated signal; means, responsive to the filtered recovered frequency modulated signal, for producing a missing zero crossing point signal containing the missing zero crossing points; deletion means, responsive to said missing zero crossing point signal, for eliminating all portions of said recovered frequency modulated signal not associated with missing zero crossing points to produce a compensation pulse representing only missing zero crossing point pairs; and means for combining said compensation pulse with said recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 81
Dependent Claim
28 words
The system of claim 76 wherein said means for combining combines only individual compensation pulses associated with missing zero crossing point pairs with said recovered frequency modulated signal.
Claim 82
Dependent Claim
78 words
The system of claim 76 wherein said deletion means includes, a delay receiving and delaying said missing zero crossing point signal, and an AND gate receiving said missing zero crossing point signal and said delayed missing zero crossing point signal received from said delay; said means for eliminating isolating pulses defining missing zero crossing points in said missing zero crossing point identifying signal to remove phase shift producing short duration pulses, unrelated to missing zero crossing points, therefrom.
Claim 83
Dependent Claim
56 words
The system of claim 76 wherein said means for eliminating includes, a low pass filter receiving and filtering said missing zero crossing point identifying signal, and a slicer slicing a portion of said filtered missing zero crossing point identifying signal around each missing zero crossing point pair to form at least one phase corrected compensation pulse.
Claim 84
Dependent Claim
64 words
The system of claim 76 wherein said means for eliminating includes, a low pass filter receiving and filtering said missing zero crossing point identifying signal, and a comparator comparing said filtered missing zero crossing point identifying signal with a threshold to remove phase shift produced short duration pulses unrelated to missing zero crossing points therefrom to form at least one phase corrected compensation pulse.
Claim 85
Dependent Claim
42 words
The system of claim 76 wherein said means for combining includes an adder for adding said individual compensation pulses produced by said means for producing to said recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 86
Dependent Claim
44 words
The system of claim 76 wherein said means for combining includes an exclusive OR gate for combining said individual compensation pulses produced by said means for producing with said recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 87
Dependent Claim
46 words
The system of claim 76 wherein said means for combining includes a comparator receiving said recovered frequency modulated signal, said comparator comparing said recovered frequency modulated signal with said at least one individual compensation pulse to produce a missing zero crossing point corrected frequency modulated signal.
Claim 88
Dependent Claim
27 words
The system of claim 76, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a tape.
Claim 89
Dependent Claim
28 words
The system of claim 76, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a frequency equalizer.
Claim 90
Independent Claim
120 words
A method of preventing an inversion phenomena in a recovered frequency modulated signal wherein at least one pair of zero crossing points are missing, comprising the steps of: (a) suppressing the lower side band of the recovered frequency modulated signal to identify all zero crossing points; (b) developing a missing zero crossing point signal containing the missing zero crossing points from the recovered frequency modulated signal and the output of said step (a); (c) eliminating all portions of the missing zero crossing point signal not associated with the missing zero crossing points to produce a compensation pulse representing only missing zero crossing point pairs; (d) combining the compensation pulse with the recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 91
Independent Claim
120 words
A method of preventing an inversion phenomena in a recovered frequency modulated signal wherein at least one pair of zero crossing points are missing, comprising the steps of: (a) suppressing the lower side band of the recovered frequency modulated signal to identify all zero crossing points; (b) developing a missing zero crossing point signal containing the missing zero crossing points from the recovered frequency modulated signal and the output of said step (a); (c) eliminating all portions of the missing zero crossing point signal not associated with the missing zero crossing points to produce a compensation pulse representing only missing zero crossing point pairs; (d) combining the compensation pulse with the recovered frequency modulated signal to inhibit the inversion phenomena.
Claim 92
Dependent Claim
27 words
The method of claim 86 wherein said step (d) combines only individual compensation pulses associated with missing zero crossing point pairs with the recovered frequency modulated signal.
Claim 93
Dependent Claim
71 words
The method of claim 86 wherein said step (c) includes the steps of, (i) delaying said missing zero crossing point signal, and (ii) logically ANDing the missing zero crossing point signal and the delayed missing zero crossing point signal, said step (c) isolating pulses defining missing zero crossing points in the missing zero crossing point signal to remove phase shift producing short duration pulses, unrelated to missing zero crossing points, therefrom.
Claim 94
Dependent Claim
58 words
The method of claim 86 wherein said step (c) includes the steps of, (i) filtering the missing zero crossing point identifying signal to attenuate high frequency components therefrom, and (ii) slicing a portion of the filtered missing zero crossing point identifying signal around each missing zero crossing point pair to form at least one phase corrected compensation pulse.
Claim 95
Dependent Claim
66 words
The method of claim 86 wherein said step (c) includes the steps of, (i) filtering the missing zero crossing point identifying signal to attenuate high frequency components therefrom, and (ii) comparing the filtered missing zero crossing point identifying signal with a threshold to remove phase shift producing short duration pulses, unrelated to missing zero crossing points, therefrom, to form at least one phase corrected compensation pulse.
Claim 96
Dependent Claim
41 words
The method of claim 86 wherein said step (d) includes the step of (i) adding the individual compensation pulses produced by said step (c) to the recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 97
Dependent Claim
43 words
The method of claim 86 wherein said step (d) includes the step of (i) logically exclusive ORing the individual compensation pulses produced by said step (c) with the recovered frequency modulated signal to produce a missing zero crossing point corrected frequency modulated signal.
Claim 98
Dependent Claim
38 words
The method of claim 86 wherein said step (d) includes the step of (i) comparing the recovered frequency modulated signal with at least one individual compensation pulse to produce a missing zero crossing point corrected frequency modulated signal.
Claim 99
Dependent Claim
27 words
The method of claim 86, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a tape.
Claim 100
Dependent Claim
28 words
The method of claim 86, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a frequency equalizer.
Claim 101
Independent Claim
124 words
A system of preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising: a compensation pulse generator for developing a missing zero crossing compensation signal for each missing pair of zero crossing points; and a missing zero crossing insertion circuit supplementing the recovered frequency modulated signal with said missing zero crossing compensation signal only around each said pair of missing zero crossing points without substantially shifting zero crossing points present in the recovered frequency modulated signal to replace each said pair of missing zero crossing points without substantial reduction in the signal to noise ratio of the frequency modulated signal.
Claim 102
Independent Claim
124 words
A system of preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising: a compensation pulse generator for developing a missing zero crossing compensation signal for each missing pair of zero crossing points; and a missing zero crossing insertion circuit supplementing the recovered frequency modulated signal with said missing zero crossing compensation signal only around each said pair of missing zero crossing points without substantially shifting zero crossing points present in the recovered frequency modulated signal to replace each said pair of missing zero crossing points without substantial reduction in the signal to noise ratio of the frequency modulated signal.
Claim 103
Dependent Claim
44 words
The system of claim 96 wherein said missing zero crossing insertion circuit adds compensation pulses to said recovered frequency modulated signal to produce a missing zero crossing point corrected signal which is not substantially phase shifted with respect to said recovered frequency modulated signal.
Claim 104
Dependent Claim
19 words
The system of claim 96 wherein said missing zero crossing insertion circuit includes a limiter at the output thereof.
Claim 105
Dependent Claim
27 words
The system of claim 96, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a tape.
Claim 106
Dependent Claim
28 words
The system of claim 96, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a frequency equalizer.
Claim 107
Independent Claim
116 words
A method of preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising the steps of: (a) developing a missing zero crossing compensation signal associated with each missing zero crossing point pair; and (b) supplementing the recovered frequency modulated signal with the missing zero crossing compensation signal only around each pair of missing zero crossing points, without substantially shifting zero crossing points present in the recovered frequency modulated signal, to replace each pair of missing zero crossing points without substantial reduction in the signal to noise ratio of the frequency modulated signal.
Claim 108
Independent Claim
116 words
A method of preventing an inversion phenomenon in a recovered frequency modulated signal, resulting from a drop out of at least one zero crossing point, wherein at least one pair of zero crossing points are missing, comprising the steps of: (a) developing a missing zero crossing compensation signal associated with each missing zero crossing point pair; and (b) supplementing the recovered frequency modulated signal with the missing zero crossing compensation signal only around each pair of missing zero crossing points, without substantially shifting zero crossing points present in the recovered frequency modulated signal, to replace each pair of missing zero crossing points without substantial reduction in the signal to noise ratio of the frequency modulated signal.
Claim 109
Dependent Claim
41 words
The method of claim 101 wherein said step (b) adds compensation pulses to said recovered frequency modulated signal to produce a missing zero crossing point corrected signal which is not substantially phase shifted with respect to the recovered frequency modulated signal.
Claim 110
Dependent Claim
19 words
The method of claim 101 wherein said step (b) includes the step of (i) limiting the supplemented recovered signal.
Claim 111
Dependent Claim
27 words
The method of claim 101, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a tape.
Claim 112
Dependent Claim
28 words
The method of claim 101, wherein said recovered frequency modulated signal is missing said at least one pair of zero crossing points when output from a frequency equalizer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-02-09 | 1996-08-10 | 1997-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-09 | 2000-08-10 | 2001-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-09 | 2004-08-10 | 2005-02-09 | $7700.00 | Window Closed / Lapsed |