JPS56129443A - Adaptive type differential pcm system and its device - Google Patents

Adaptive type differential pcm system and its device

Info

Publication number
JPS56129443A
JPS56129443A JP3283880A JP3283880A JPS56129443A JP S56129443 A JPS56129443 A JP S56129443A JP 3283880 A JP3283880 A JP 3283880A JP 3283880 A JP3283880 A JP 3283880A JP S56129443 A JPS56129443 A JP S56129443A
Authority
JP
Japan
Prior art keywords
value
circuit
input
output
forecast
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.)
Granted
Application number
JP3283880A
Other languages
Japanese (ja)
Other versions
JPS6251541B2 (en
Inventor
Kazunori Ozawa
Kazuo Ochiai
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.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric Co Ltd
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 NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP3283880A priority Critical patent/JPS56129443A/en
Publication of JPS56129443A publication Critical patent/JPS56129443A/en
Publication of JPS6251541B2 publication Critical patent/JPS6251541B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/04—Differential modulation with several bits, e.g. differential pulse code modulation [DPCM]
    • H03M3/042—Differential modulation with several bits, e.g. differential pulse code modulation [DPCM] with adaptable step size, e.g. adaptive differential pulse code modulation [ADPCM]

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)

Abstract

PURPOSE:To enable high quality transmission and to enable to obtain very low symbol error rate to data MODEM signal, by decreasing the correcting speed in the forecast coefficient correcting circuit, in a backward type ADPCM system. CONSTITUTION:At the transmission side 11, the input value ej of the adaptive type forecast device 14 and the output value xj are added by using an adder 31, and this outputs is fed to the product sum circuit 32. The circuit 32 outputs square leakage integrating value X. On the other hand, the output value ej of the adaptive type inverse quantization device 18 is input to the circuit 36 to output square leakage integration value y. The discriminating circuit 37 takes ratio of the input X and Y and compares it with the predetermined value every sampling time, and if is exceeds a given value, the discriminating signal Z is output to the backward type adaptive forecast coefficient value correction circuit 22. This correction circuit 22 is set to a small predetermined value than the value used at one sampling time part or 0, to correct the forecast coefficient. Thus, if the forecast coefficient value suitable for input signal is obtained, almost further correction is not made. This is the same for the reception side 20.
JP3283880A 1980-03-14 1980-03-14 Adaptive type differential pcm system and its device Granted JPS56129443A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3283880A JPS56129443A (en) 1980-03-14 1980-03-14 Adaptive type differential pcm system and its device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3283880A JPS56129443A (en) 1980-03-14 1980-03-14 Adaptive type differential pcm system and its device

Publications (2)

Publication Number Publication Date
JPS56129443A true JPS56129443A (en) 1981-10-09
JPS6251541B2 JPS6251541B2 (en) 1987-10-30

Family

ID=12369956

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3283880A Granted JPS56129443A (en) 1980-03-14 1980-03-14 Adaptive type differential pcm system and its device

Country Status (1)

Country Link
JP (1) JPS56129443A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59500077A (en) * 1982-01-27 1984-01-12 ウエスタ−ン　エレクトリツク　カムパニ−，インコ−ポレ−テツド Adaptive differential PCM encoder
EP0206273A2 (en) * 1985-06-20 1986-12-30 Fujitsu Limited Adaptive differential pulse code modulation system
JPH01268317A (en) * 1988-04-20 1989-10-26 Sanyo Electric Co Ltd Decoding device for adpcm signal

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59500077A (en) * 1982-01-27 1984-01-12 ウエスタ−ン　エレクトリツク　カムパニ−，インコ−ポレ−テツド Adaptive differential PCM encoder
JPH0133976B2 (en) * 1982-01-27 1989-07-17 Ei Teii Ando Teii Tekunorojiizu Inc
EP0206273A2 (en) * 1985-06-20 1986-12-30 Fujitsu Limited Adaptive differential pulse code modulation system
JPH01268317A (en) * 1988-04-20 1989-10-26 Sanyo Electric Co Ltd Decoding device for adpcm signal

Also Published As

Publication number Publication date
JPS6251541B2 (en) 1987-10-30

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