US4229830A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for providing a modulation format for multiple wideband signal transmission
Assignee: Ampex Corp
•
Filing: 1979-06-01
•
Granted: 1980-10-21
•
Expires: 1999-06-01
Abstract
Abstract A modulation format for containing, for simultaneously transmitting via a single optical fiber, and for decoding, multiple independent wideband signals. The format derives maximum advantage from the inherent wideband properties of the optical fiber, while utilizing the concept that the signal-to-noise ratio of one channel (e.g., in a red, green, and blue color video signal) is preferably made substantially greater than that for the other two channels. This allows optimizing the signal-to-noise ratio of the signal channels while using a relatively simplified circuit implementation. To this end, the format waveform employs a stationary reference edge and multiple time-variable edges, wherein the time interval between the reference edge and the following time-variable edge of the same polarity always exceeds, or always is less than, one-half of the total available time period of the waveform. That is, the next time-variable edge of the same polarity as the stationary reference edge never crosses the half-way point of the total time period of the waveform in the course of being deviated. The above conditions allow a relatively simplified edge discrimination scheme and demultiplexing circuit.
Inventors
- 👤 John O. Ryan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:21
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/22; H04J; H04J3/00; H04J3/16; H04J3/1676; H04J7/00
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
128 words
A circuit for generating and utilizing a modulation format for transmitting multiple wideband signals of respective signal channels via a single optical fiber, the combination comprising; generating means including modulator means for generating said modulation format in the form of a waveform of a given time period having a stationary reference edge and multiple time deviable edges, wherein the position of each latter edge is time varied relative to the stationary reference edge in accordance with respective sampled signals of the corresponding signal channels, and; receiving means including demultiplexer means operatively coupled to the generating means via said single optical fiber, for detecting the stationary reference edge and for separating the multiple time deviable edges with respect to the stationary reference edge to recover the multiple wideband signals.
Claim 2
Dependent Claim
128 words
A circuit for generating and utilizing a modulation format for transmitting multiple wideband signals of respective signal channels via a single optical fiber, the combination comprising; generating means including modulator means for generating said modulation format in the form of a waveform of a given time period having a stationary reference edge and multiple time deviable edges, wherein the position of each latter edge is time varied relative to the stationary reference edge in accordance with respective sampled signals of the corresponding signal channels, and; receiving means including demultiplexer means operatively coupled to the generating means via said single optical fiber, for detecting the stationary reference edge and for separating the multiple time deviable edges with respect to the stationary reference edge to recover the multiple wideband signals.
Claim 3
Dependent Claim
39 words
The circuit of claim 1 wherein the next time deviable edge of the same polarity as the stationary reference edge only approaches and never crosses the half-way point of the total waveform period in the course of its deviation.
Claim 4
Dependent Claim
31 words
The circuit of claim 2 wherein at least two wideband signals of two corresponding signal channels are modulated via the modulation format by corresponding time deviations of respective time deviable edges.
Claim 5
Dependent Claim
29 words
The circuit of claim 2 wherein three wideband signals of three corresponding signal channels are modulated via the modulation format by corresponding time deviations of respective time deviable edges.
Claim 6
Dependent Claim
39 words
The circuit of claim 2 wherein the wideband signals correspond to color components of a composite color video signal, and wherein a selected color component is represented by the multiple time deviable edge which has the greatest time deviation.
Claim 7
Dependent Claim
51 words
The circuit of claim 5 wherein the generating means includes; sampling means for sampling at a given frequency each wideband signal of respective signal channels; and wherein the sampled signals of respective channels deviate in time with the respective deviable edges in accordance with the sampled values at the given frequency.
Claim 8
Dependent Claim
53 words
The circuit of claim 6 wherein the modulator means includes; oscillator means for generating a selected driving waveform of said given sampling frequency; and a differential comparator in each channel for comparing the level of the driving waveform with the respective wideband signals to determine the positions of the respective time deviable edges.
Claim 9
Dependent Claim
42 words
The circuit of claim 7 wherein; the receiving means includes edge discriminator means for detecting the stationary reference edge, and for detecting the next time deviable edge of the same polarity which never crosses the half-way point of the total waveform period.
Claim 10
Dependent Claim
39 words
The circuit of claim 8 wherein; the edge discriminator means includes, binary divider means with complimentary outputs, and comparator means coupled to the complimentary outputs for selecting that output thereof which goes positive in response to the reference edge.
Claim 11
Dependent Claim
66 words
The circuit of claim 9 wherein the receiving means further includes; light detecting means coupled to the single optical fiber to receive the transmitted modulation format; phase locked oscillator means selectively coupled to the complimentary outputs of the binary divider means in response to the comparator means; and wherein the demultiplexer means is coupled to the light detecting means and to the phase locked oscillator means.
Claim 12
Dependent Claim
30 words
The circuit of claim 10 wherein; said sampling means includes a sample/hold circuit in each wideband signal channel, and clock means for driving the sample/hold circuits at the given frequency.
Claim 13
Dependent Claim
45 words
The circuit of claim 10 wherein the modulator means further includes transistor pairs defining the differential comparator in each signal channel, current source means selectively coupled to each of the transistor pairs, and gate means coupled to the transistor pairs to generate the modulation format.
Claim 14
Dependent Claim
48 words
The circuit of claim 12 wherein; the comparator means is coupled to the complimentary outputs of the binary divider means to select the output thereof with the greatest average D.C. level to define the portion of the waveform period which always exceeds one-half of the total waveform period.
Claim 15
Dependent Claim
35 words
The circuit of claim 13 further including switch means coupled to the complimentary outputs of the binary divider means and responsive to the comparator means to select the output with the greatest average D.C. level.
Claim 16
Dependent Claim
41 words
The circuit of claim 14 wherein; the demultiplexer means includes flip-flop means in each signal channel responsive to the phase locked oscillator and to the respective time deviable edges, to selectively regenerate the time deviable edges relative to the reference edge.
Claim 17
Dependent Claim
50 words
The circuit of claim 12 wherein; the comparator means is coupled to the complimentary outputs of the binary divider means to select the output thereof with the smallest average D.C. level to define the portion of the waveform period which is always less than one-half of the total waveform period.
Claim 18
Dependent Claim
34 words
The circuit of claim 16 further including switch means coupled to the outputs of the binary divider means and responsive to the comparator means to select the output with the smallest average D.C. level.
Claim 19
Dependent Claim
41 words
The circuit of claim 17 wherein; the demultiplexer means includes flip-flop means in each signal channel responsive to the phase locked oscillator and to the respective time deviable edges, to selectively regenerate the time deviable edges relative to the reference edge.
Claim 20
Dependent Claim
70 words
A circuit for generating a modulation format for representing multiple wideband signals of respective signal channels, the combination comprising; waveform generating means including modulator means for generating the format in the form of a waveform of time period 1/F which includes a stationary reference edge, and multiple time-variable edges each of whose positions vary with respect to the stationary reference edge in accordance with sampled magnitudes of their respective signals.
Claim 21
Dependent Claim
70 words
A circuit for generating a modulation format for representing multiple wideband signals of respective signal channels, the combination comprising; waveform generating means including modulator means for generating the format in the form of a waveform of time period 1/F which includes a stationary reference edge, and multiple time-variable edges each of whose positions vary with respect to the stationary reference edge in accordance with sampled magnitudes of their respective signals.
Claim 22
Dependent Claim
39 words
The circuit of claim 19 wherein the next time-variable edge of the same polarity as the stationary edge may approach and never cross the half-way point of the total available waveform time period in the course of being deviated.
Claim 23
Dependent Claim
31 words
The circuit of claim 20 wherein; the time interval between the stationary reference edge and the next time-variable edge of the same polarity always exceeds one-half of the total waveform period.
Claim 24
Dependent Claim
33 words
The circuit of claim 20 wherein; the time interval between the stationary reference edge and the next time-variable edge of the same polarity is always less than one-half of the total waveform period.
Claim 25
Independent Claim
87 words
A method for providing an improved modulation format which is capable of representing multiple wideband signals of respective signal channels, comprising the steps of; selectively sampling at a given sampling frequency each of the wideband signals to determine their instantaneous values; and generating the modulation format as a waveform of a given time period, with a stationary reference edge, and with multiple time deviable edges each of whose positions with respect to the stationary reference edge varies in time in accordance with the respective sampled wideband signals.
Claim 26
Independent Claim
87 words
A method for providing an improved modulation format which is capable of representing multiple wideband signals of respective signal channels, comprising the steps of; selectively sampling at a given sampling frequency each of the wideband signals to determine their instantaneous values; and generating the modulation format as a waveform of a given time period, with a stationary reference edge, and with multiple time deviable edges each of whose positions with respect to the stationary reference edge varies in time in accordance with the respective sampled wideband signals.
Claim 27
Dependent Claim
50 words
The method of claim 23 wherein the step of generating the time deviable edges includes generating a next time deviable edge of the same polarity as the reference edge which may approach and never cross the half-way point of the given waveform time period in the course of its deviation.
Claim 28
Dependent Claim
57 words
The method of claim 24 further providing for utilizing the modulation format representing the multiple wideband signals, and including the steps of; transmitting the waveform via a single optical fiber; detecting the stationary reference edge of the transmitted waveform; and demultiplexing the time deviable edges with respect to the stationary reference edge to retrieve the wideband signals.
Claim 29
Dependent Claim
47 words
The method of claim 25 further comprising; generating a triangular wave of said given sampling frequency; comparing the levels of the triangular wave with each of the respective wideband signals to determine the positions of the respective time deviable edges with respect to the stationary reference edge.
Claim 30
Dependent Claim
39 words
The method of claim 26 wherein the step of detecting the stationary reference edge includes; comparing the average D.C. levels of a pair of complimentary outputs to select that output which goes positive in response to the reference edge.
Claim 31
Dependent Claim
38 words
The method of claim 27 wherein the step of demultiplexing the time deviable edges includes; maintaining a phase locked oscillator at the given sampling frequency; and regenerating the time deviable edges with respect to the stationary reference edge.
References Cited (Backward Citations)
FR2343384A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-21 | 1984-04-21 | 1984-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-21 | 1988-04-21 | 1988-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-21 | 1992-04-21 | 1992-10-21 | $7700.00 | Window Closed / Lapsed |