GB1501874A - Telecommunications apparatus - Google Patents

Telecommunications apparatus

Info

Publication number
GB1501874A
GB1501874A GB25475/74A GB2547574A GB1501874A GB 1501874 A GB1501874 A GB 1501874A GB 25475/74 A GB25475/74 A GB 25475/74A GB 2547574 A GB2547574 A GB 2547574A GB 1501874 A GB1501874 A GB 1501874A
Authority
GB
United Kingdom
Prior art keywords
time interval
decoder
amplitude
coder
code
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB25475/74A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UK Secretary of State for Defence
Original Assignee
UK Secretary of State for Defence
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by UK Secretary of State for Defence filed Critical UK Secretary of State for Defence
Priority to GB25475/74A priority Critical patent/GB1501874A/en
Publication of GB1501874A publication Critical patent/GB1501874A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/66—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
    • G10L25/00—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/34—Analogue value compared with reference values

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Theoretical Computer Science (AREA)
  • Computational Linguistics (AREA)
  • Health & Medical Sciences (AREA)
  • Audiology, Speech & Language Pathology (AREA)
  • Human Computer Interaction (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)

Abstract

1501874 Speech transmission DEFENCE SECRETARY OF STATE FOR 3 June 1975 [7 June 1974] 25475/74 Heading H4R In a pulse code modulation system, the logarithmically compressed amplitudes of, and time intervals between, successive stationary points (maxima and minima) of an input analogue waveform are encoded, and the decoder includes a filter whose response time is controlled in accordance with the received time interval signals. Coder.-Stationary points are detected by a differentiator 2 and zero cross detector 4 which controls the sampling instants for the amplitude coder 6 and the time interval coder 7, either or both of which may have a compressive characteristic. Decoder.-Timer 15 controls read out of time interval and amplitude codes from buffer 13 in accordance with the time interval codes. Amplitude decoder 17 produces a stepped wave analogue output in which each level has a duration corresponding to a respective time interval code and this stepped wave is smoothed in a second order controllable filter 19, details Fig. 3 (not shown) comprising impedances which are switched in and out of circuit with a variable duty-cycle determined by the time interval decoder 16 to match the rise time of the filter to the duration of each step in the output of the amplitude decoder 17. Transmission link.-In order that the P.C.M. signals may be transmitted at a predetermined regular bit rate, despite irregular sampling, buffer stores 8, 13 are provided and the transmission link has a slight excess capacity. When multiplexer 9 finds an empty store location, a zero time interval code is transmitted together with a repetition of the previous amplitude code.
GB25475/74A 1975-06-03 1975-06-03 Telecommunications apparatus Expired GB1501874A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB25475/74A GB1501874A (en) 1975-06-03 1975-06-03 Telecommunications apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB25475/74A GB1501874A (en) 1975-06-03 1975-06-03 Telecommunications apparatus

Publications (1)

Publication Number Publication Date
GB1501874A true GB1501874A (en) 1978-02-22

Family

ID=10228315

Family Applications (1)

Application Number Title Priority Date Filing Date
GB25475/74A Expired GB1501874A (en) 1975-06-03 1975-06-03 Telecommunications apparatus

Country Status (1)

Country Link
GB (1) GB1501874A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0004759A2 (en) * 1978-04-04 1979-10-17 National Research Development Corporation Methods and apparatus for encoding and constructing signals
FR2524225A1 (en) * 1982-03-26 1983-09-30 Victor Company Of Japan METHOD AND SYSTEM FOR DECODING A DIGITAL SIGNAL USING A LOW-PASS FILTER FOR VARIABLE FREQUENCY
EP0093190A1 (en) * 1982-05-05 1983-11-09 Arie Visser Extrema coding signal processing method and apparatus
US4545065A (en) * 1982-04-28 1985-10-01 Xsi General Partnership Extrema coding signal processing method and apparatus
US4652857A (en) * 1983-04-29 1987-03-24 Meiksin Zvi H Method and apparatus for transmitting wide-bandwidth frequency signals from mines and other power restricted environments
EP0491840A1 (en) * 1989-09-13 1992-07-01 Datajet, Inc. Signal digitizing method and system
FR2697388A1 (en) * 1992-10-22 1994-04-29 Eurodat Dynamic Analogue=digital converter - includes sample=and=hold circuit and comparator comparing successive values of signal, with comparator output values stored with related times

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0004759A2 (en) * 1978-04-04 1979-10-17 National Research Development Corporation Methods and apparatus for encoding and constructing signals
EP0004759A3 (en) * 1978-04-04 1979-10-31 Harold William Gosling Methods and apparatus for encoding and constructing signals
US4382160A (en) 1978-04-04 1983-05-03 National Research Development Corporation Methods and apparatus for encoding and constructing signals
FR2524225A1 (en) * 1982-03-26 1983-09-30 Victor Company Of Japan METHOD AND SYSTEM FOR DECODING A DIGITAL SIGNAL USING A LOW-PASS FILTER FOR VARIABLE FREQUENCY
US4673916A (en) * 1982-03-26 1987-06-16 Victor Company Of Japan, Limited Method and system for decoding a digital signal using a variable frequency low-pass filter
US4545065A (en) * 1982-04-28 1985-10-01 Xsi General Partnership Extrema coding signal processing method and apparatus
EP0093190A1 (en) * 1982-05-05 1983-11-09 Arie Visser Extrema coding signal processing method and apparatus
US4652857A (en) * 1983-04-29 1987-03-24 Meiksin Zvi H Method and apparatus for transmitting wide-bandwidth frequency signals from mines and other power restricted environments
EP0491840A1 (en) * 1989-09-13 1992-07-01 Datajet, Inc. Signal digitizing method and system
EP0491840A4 (en) * 1989-09-13 1994-11-02 Datajet Inc Signal digitizing method and system
FR2697388A1 (en) * 1992-10-22 1994-04-29 Eurodat Dynamic Analogue=digital converter - includes sample=and=hold circuit and comparator comparing successive values of signal, with comparator output values stored with related times

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee