US3843940A
Expired / Lapsed
US
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Differential pulse code modulation transmission system
Assignee: NEC Corp
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Filing: 1973-10-11
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Granted: 1974-10-22
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Expires: 1993-10-11
Abstract
Abstract Two embodiments of a transmission system capable of the direct encoding of frequency multiplexed color television signals into differential pulse code modulation signals are disclosed. In the first embodiment, the transmitter includes a pre-emphasis filter whose transfer function assumes a minimum value in the vicinity of the frequency of the color subcarrier signal. The output of the pre-emphasis filter is connected to a noise feedback pulse code modulation coder which delivers quantized signals as its output. A code converter converts the quantized signals to a differential pulse code modulated signal for transmission. The receiver includes a de-emphasis filter having the inverse transfer function of said pre-emphasis filter. The second embodiment is equivalent to the first but instead of a preemphasis filter employs a predictive filter connected in a feedback path around the quantizer. The transfer function P of the predictive filter is such that the value (1-P) assumes a minimum value in the vicinity of the frequency of the subcarrier signal.
Inventors
- 👤 T Ishiguro
- 👤 Y Iijima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:07
CPC Classifications
H; H03; H03M; H03M7/00; H03M7/30; H03M7/3002; H03M7/3044; H04; H04B; H04B1/00; H04B1/62; H04N; H04N11/00; H04N11/04; H04N11/042; H04N11/046
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
267 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier signal, comprising: a transmitter including, A. a pre-emphasis filter, whose transfer function H assumes a minimum value nearly equal to zero in the vicinity of the frequency of said subcarrier signal, and which delivers a prediction error signal determined by said transfer function H, B. a noise feedback PCM coder, coupled to the output of said preemphasis filter, having (a) an adder for calculating the sum of the output of said pre-emphasis filter and an adding input signal, (b) a quantizer for quantizing the output of said adder to deliver quantized signals each representing the input signal thereof ranging within the respective predetermined quantizing range, (c) a subtractor for calculating the difference between the input and output of said quantizer, and (d) a noise feedback filter whose transfer function F is set so that the value (1-F) assumes a minimum value nearly equal to zero in the vicinity of the frequency of said subcarrier signal, and which delivers said adding input signal, and C. a code converter for applying a code conversion to said quantized signals thereby to transmit a differential pulse code modulation signal corresponding to said frequency division multiplexed signal to a receiver via a transmission line; and said receiver including, D. a code converter for receiving the transmitted differential pulse code modulation signal, and for regenerating said quantized signals, and E. a decoder, coupled to the last-mentioned code converter, which has the inverse transfer function of said transfer function H, thereby to regenerate said frequency division multiplexed signal.
Claim 2
Dependent Claim
267 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier signal, comprising: a transmitter including, A. a pre-emphasis filter, whose transfer function H assumes a minimum value nearly equal to zero in the vicinity of the frequency of said subcarrier signal, and which delivers a prediction error signal determined by said transfer function H, B. a noise feedback PCM coder, coupled to the output of said preemphasis filter, having (a) an adder for calculating the sum of the output of said pre-emphasis filter and an adding input signal, (b) a quantizer for quantizing the output of said adder to deliver quantized signals each representing the input signal thereof ranging within the respective predetermined quantizing range, (c) a subtractor for calculating the difference between the input and output of said quantizer, and (d) a noise feedback filter whose transfer function F is set so that the value (1-F) assumes a minimum value nearly equal to zero in the vicinity of the frequency of said subcarrier signal, and which delivers said adding input signal, and C. a code converter for applying a code conversion to said quantized signals thereby to transmit a differential pulse code modulation signal corresponding to said frequency division multiplexed signal to a receiver via a transmission line; and said receiver including, D. a code converter for receiving the transmitted differential pulse code modulation signal, and for regenerating said quantized signals, and E. a decoder, coupled to the last-mentioned code converter, which has the inverse transfer function of said transfer function H, thereby to regenerate said frequency division multiplexed signal.
Claim 3
Dependent Claim
246 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier signal, comprising: a transmitter including, A. a subtractor for calculating the difference between said frequency division multiplexed signal and a subtracting input signal, B. a quantizer for quantizing the output of said subtractor to deliver quantized signals each representing the input signal thereof ranging within the respective predetermined quantizing range, C. an adder for calculating the sum of the output of said quantizer and an adding input signal, D. a predictive filter, coupled to the output of said adder, whose transfer function P bears the relationship to a transfer function H such that P 1-H and P is set so that the value (1-P) assumes a minimum value nearly equal to zero in the vicinity of the frequency of said subcarrier signal, thereby to supply the output signal thereof to said subtractor and adder as said subtracting and adding input signals, and E. a code converter for applying a code conversion to said quantized signals thereby to transmit a differential pulse code modulation signal corresponding to said frequency division multiplexed signal to a receiver via a transmission line; and said receiver including, F. a code converter for receiving the transmitted differential pulse code modulation signal, and for regenerating said quantized signals, and G. a dEcoder, coupled to the last-mentioned code converter, which has the inverse tranfer function of said transfer function H, thereby to regenerate said frequency division multiplexed signal.
Claim 4
Dependent Claim
246 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier signal, comprising: a transmitter including, A. a subtractor for calculating the difference between said frequency division multiplexed signal and a subtracting input signal, B. a quantizer for quantizing the output of said subtractor to deliver quantized signals each representing the input signal thereof ranging within the respective predetermined quantizing range, C. an adder for calculating the sum of the output of said quantizer and an adding input signal, D. a predictive filter, coupled to the output of said adder, whose transfer function P bears the relationship to a transfer function H such that P 1-H and P is set so that the value (1-P) assumes a minimum value nearly equal to zero in the vicinity of the frequency of said subcarrier signal, thereby to supply the output signal thereof to said subtractor and adder as said subtracting and adding input signals, and E. a code converter for applying a code conversion to said quantized signals thereby to transmit a differential pulse code modulation signal corresponding to said frequency division multiplexed signal to a receiver via a transmission line; and said receiver including, F. a code converter for receiving the transmitted differential pulse code modulation signal, and for regenerating said quantized signals, and G. a dEcoder, coupled to the last-mentioned code converter, which has the inverse tranfer function of said transfer function H, thereby to regenerate said frequency division multiplexed signal.
Claim 5
Dependent Claim
66 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier as recited in claim 1 further comprising an analog-digital converter in said transmitter connected to the input of said pre-emphasis filter and a digital-analog converter in said receiver connected to the output of said decoder, and wherein said pre-emphasis filter, said noise feedback filter and said decoder are digital filters.
Claim 6
Dependent Claim
72 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier as recited in claim 1 wherein said transfer function H is represented by a Z-transform including the factor (1- Alpha Z n) when fsc about fs/n where fsc is the frequency of said subcarrier signal, fs is the sampling frequency of said quantizer, Alpha is a constant less than one, and n is a positive integer.
Claim 7
Dependent Claim
61 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier as recited in claim 2 further comprising an analog-digital converter in said transmitter connected to the input of said subtractor and a digital-analog converter in said receiver connected to the output of said decoder, and wherein said predictive filter and said decoder are digital filters.
Claim 8
Dependent Claim
71 words
A differential pulse code modulation transmission system for a frequency division multiplexed signal having a subcarrier as recited in claim 2 wherein the value (1-P) is represented by a Z-transform including the factor (1- Alpha Z n) when fsc about fs/n where fsc is the frequency of said subcarrier signal, fs is the sampling frequency of said quantizer, Alpha is a constant less than one, and n is a positive integer.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |