US3560659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for the transmission of analogue signals by means of pulse code modulation
Assignee: US Philips Corp
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Filing: 1968-09-03
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Granted: 1971-02-02
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Expires: 1988-09-03
Abstract
Abstract A pulse code modulation system for the transmission of analogue signals by converting prior to transmission successive samples of the analogue signal supplied by a level signal generator to an analogue to digital converter having dynamic high compression feedback control circuits for producing coded groups of pulses having different weights and numbers characterizing the analogue signals. After transmission, the coded groups of pulses are supplied to a digital to analogue converter, having characteristics reciprocal to those of the transmitter''s analogue to digital converter, and a dynamic expansion control circuit, having reciprocal characteristics of the transmitter''s compression circuits to produce exact reproductions of the original analogue signals.
Inventors
- 👤 Johannes Anton Greefkes
- 👤 Henricus Petrus Joh Boudewijns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:45
CPC Classifications
H; H04; H04B; H04B14/00; H04B14/02; H04B14/04; H04B14/046; H04B14/048
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
253 words
A pulse code modulation system for the transmission of analogue signals from a transmitting terminal to a receiving terminal, comprising at said transmitting terminal, analogue signal input means, level signal generating means for producing signals characterizing the analogue signals, pulse generating means for producing control pulses, sampling means activated by said control pulses for providing successive signal increments from the output signals of said level signal generating means, analogue-to-digital converting means for coding the output signals from said sampling means to produce groups of pulses having different weights, compression control means for providing additional coding of the code groups produced by said analogueto-digital converting means, means for transmitting the pulse code groups to the receiving means, and comprising at said receiving means, pulse regenerating means for processing the pulses in the code groups, digital-to-analogue converting means having characteristics of said analogue-to-digital converting means in the transmitter, said digital-to-analogue converting means for producing decoded signals from the pulses in the coded groups being supplied from said pulse regenerating means, expansion control means having characteristics mutually reciprocal to the characteristics of said compression control means in the transmitter, said expansion control means controlling said digital-to-analogue converting means, pulse generating means to produce control pulses in synchronism with the control pulses of the transmitter, commutating means activated by the control pulses of said pulse generating means for synthesizing the decoded signals from said digital-toanalogue converting means, and reproduction means for producing from the decoded signals analogue signals identical to the analogue signals supplied to the transmitter.
Claim 2
Dependent Claim
253 words
A pulse code modulation system for the transmission of analogue signals from a transmitting terminal to a receiving terminal, comprising at said transmitting terminal, analogue signal input means, level signal generating means for producing signals characterizing the analogue signals, pulse generating means for producing control pulses, sampling means activated by said control pulses for providing successive signal increments from the output signals of said level signal generating means, analogue-to-digital converting means for coding the output signals from said sampling means to produce groups of pulses having different weights, compression control means for providing additional coding of the code groups produced by said analogueto-digital converting means, means for transmitting the pulse code groups to the receiving means, and comprising at said receiving means, pulse regenerating means for processing the pulses in the code groups, digital-to-analogue converting means having characteristics of said analogue-to-digital converting means in the transmitter, said digital-to-analogue converting means for producing decoded signals from the pulses in the coded groups being supplied from said pulse regenerating means, expansion control means having characteristics mutually reciprocal to the characteristics of said compression control means in the transmitter, said expansion control means controlling said digital-to-analogue converting means, pulse generating means to produce control pulses in synchronism with the control pulses of the transmitter, commutating means activated by the control pulses of said pulse generating means for synthesizing the decoded signals from said digital-toanalogue converting means, and reproduction means for producing from the decoded signals analogue signals identical to the analogue signals supplied to the transmitter.
Claim 3
Dependent Claim
34 words
A pulse code modulation system as claimed in claim 1, wherein said level signal generating means comprises a combination device in parallel with a series circuit consisting of a rectifier and a low-pass filter.
Claim 4
Dependent Claim
55 words
A pulse code modulation system as claimed in claim 7, wherein said level signal generating means comprises a full wave rectifier for providing analogue signal leVels to said sampling means and pulse means for characterizing polarity of the analogue signals to be transmitted by simultaneously combining polarity signals with the coded groups prior to transmission.
Claim 5
Dependent Claim
41 words
A pulse code modulation system as claimed in claim 1, wherein said level signal generating means comprises integrating means supplied by the control pulses of said pulse generating means, and amplitude modulating means for controlling the output of said integrating means.
Claim 6
Dependent Claim
157 words
A pulse code modulating system as claimed in claim 1, wherein the compression control means comprises gating means activated by said pulse generating means to pass a number of pulses of the coded groups produced by said analogue-to-digital converting means, integrating means for producing voltages from the pulses passed by said gating means, comparator means for comparing the voltage of said integrating means with a reference signal to produce dynamic compression control voltages inversely proportional to the integrated voltage, analogue-to-digital converter control means to produce coding pulses from the control pulses of said pulse generating means, and amplitude modulating means controlled by the control voltage from said comparator means to vary the amplitude of the coding pulses supplied to said analogue-to-digital converting means and produce from said analogue-to-digital converting means coded groups of pulses of different weights, the presence or absences of said pulses being directly proportional to the number of pulses passed by said gating means.
Claim 7
Dependent Claim
140 words
A pulse code modulation system as claimed in claim 1, wherein the expansion control means comprises gating means activated by said pulse generating means to a number of pulses of the coded groups from said pulse regenerating means, integrating means for producing voltages passed by said gating means, comparator means for comparing the voltage of said integrating means, with a reference signal to produce dynamic expansion control voltages inversely proportional to the integrated voltage, digital-to-analogue converter control means to produce coding pulses from the control pulses of said pulse generating means and amplitude modulating means controlled by the control voltage from said comparator means to vary the amplitude of the coding pulses supplied to said digital-to-analogue converting means and produce from said digital-to-analogue converting means signals with characteristics determined by the coded groups of pulses from said pulse regenerating means.
Claim 8
Dependent Claim
125 words
A pulse code modulation system as claimed in claim 1, wherein the analogue-to-digital converting means comprises a capacitor charged by the output signals from said sampling means, a ladder network of resistors connected to said capacitor to provide weight factors for the pulses, reference voltage generating means controlled by said pulse generating means, for comparing the voltage on said capacitor with the voltage from said reference voltage generating means to provide difference voltages, frequency multiplying means for increasing the frequency of the pulses from said pulse generating means and pulse modulating means for modulating the output pulses of said frequency multiplier in accordance with the magnitude and polarity of the difference voltage from said comparing means to produce coded groups of pulses having different weights.
Claim 9
Dependent Claim
90 words
A pulse code modulation system as claimed in claim 1, wherein said analogue-to-digital converting means further comprises pulse duration modulating means to provide pulses of varying duration characterizing the output pulses from said sampling means, frequency multiplying means for increasing the frequency of the control pulses from said pulse generating means, gating means controlled by the varying pulses of said pulse duration modulator to pass the pulses from said frequency multiplying means and digital means to produce coded groups of pulses from the output of said gating means for transmission.
Claim 10
Dependent Claim
93 words
A pulse code modulation system as claimed in claim 1, wherein the digital-to-analogue converting means comprises a capacitor, a ladder network of resistors connected to said capacitor to provide weight factors for the pulses, a plurality of normally closed current sources connected to the parallel branches of said ladder network to increase the charge on said capacitor by a given amount, and commutating means controlled by said pulse generating means for controlling said normally closed current sources in proportion to the number of pulses in the coded groups from said pulse regenerating means.
Claim 11
Dependent Claim
51 words
A pulse code modulation system as claimed in claim 1, wherein said pulse regenerative means comprises gating means supplied with said coded groups of pulses to suppress pulses of opposite polarity from said digital-to-analogue converting means, and provide means for controlling the polarity of the output of said digital-to-analogue converting means.
Claim 12
Dependent Claim
47 words
A pulse code modulation system as claimed in claim 1, further comprising a plurality of signal processing and level signal generating channels, a plurality of compression control means equal to the number of said channels, and commutating means for providing time-multiplex operation of said analogue-to-digital converting means.
Claim 13
Dependent Claim
43 words
A pulse code, modulation system as claimed in claim 1, further comprising a plurality of expansion control means, commutating means for providing time-multiplex operation of said digital-to-analogue converting means to a plurality of reproduction means equal to the number of expansion control means.
Claim 14
Dependent Claim
35 words
A pulse code modulation system as claimed in claim 5, wherein the compression control means further comprises a plurality of gating means, and an equal number of integrating means for operation with said gating means.
Claim 15
Dependent Claim
37 words
A pulse code modulation system as claimed in claim 5, wherein said integrating means comprises a first section having a cutoff frequency of the order of the low frequency of the output signal from said sampling means.
Claim 16
Dependent Claim
35 words
A pulse code modulation system as claimed in claim 6, wherein said expansion control means further comprises a plurality of gating means, and an equal number of integrating means for operation with said gating means.
Claim 17
Dependent Claim
63 words
A pulse code modulation system as claimed in claim 7, wherein said analogue-to-digital converting means further comprises commutating means controlled by said pulse generating means, and a plurality of normally closed current sources connected between said commutating means and the parallel branches of said ladder network and controlled by said commutating means to reduce the charge on said capacitor by a given amount.
Claim 18
Dependent Claim
54 words
A pulse code modulation system as claimed in claim 13, wherein said integrating means further comprises a second section connected in cascade with said first section, said second section having a cutoff frequency higher than that of said first section but not exceeding the low frequency of the output signal from said sampling means.
References Cited (Backward Citations)
US2897275A
Cited
US3461244A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |