GB1528954A - Digital attenuator - Google Patents

Digital attenuator

Info

Publication number
GB1528954A
GB1528954A GB23457/75A GB2345775A GB1528954A GB 1528954 A GB1528954 A GB 1528954A GB 23457/75 A GB23457/75 A GB 23457/75A GB 2345775 A GB2345775 A GB 2345775A GB 1528954 A GB1528954 A GB 1528954A
Authority
GB
United Kingdom
Prior art keywords
signal
shift register
input
digital attenuator
companded
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
GB23457/75A
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.)
Post Office
Original Assignee
Post Office
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 Post Office filed Critical Post Office
Priority to GB23457/75A priority Critical patent/GB1528954A/en
Priority to NL7605703A priority patent/NL7605703A/en
Priority to SE7606014A priority patent/SE7606014L/en
Priority to FR7616180A priority patent/FR2312883A1/en
Priority to DE19762624257 priority patent/DE2624257A1/en
Publication of GB1528954A publication Critical patent/GB1528954A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/02—Digital function generators
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F5/00—Methods or arrangements for data conversion without changing the order or content of the data handled
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H17/00—Networks using digital techniques
    • H03H17/0054—Attenuators
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
    • H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
    • H03M7/50—Conversion to or from non-linear codes, e.g. companding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation
    • H04B14/04—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation using pulse code modulation
    • H04B14/046—Systems or methods for reducing noise or bandwidth
    • H04B14/048—Non linear compression or expansion

Abstract

1528954 Digital attenuator POST OFFICE 27 May 1976 [29 May 1975] 23457/75 Heading H4R In a digital attenuator for providing a predetermined attenuation to a companded p.c.m. signal the input signal is fed into a shift register B1, B2, B3, B4, through which the bits are serially shifted, with the original bit sequence sensed and the logical state of at least one bit modified to provide a signal at the shift register output which represents a predetermined fraction of the value represented by the shift register output. As described the input signal is a p.c.m. signal companded according to the A-law and according to the particular segment in which the signal lies at any instant, as determined by the logical state of the second, third and fourth digits of the coded signal, the first digit being a sign digit, the interconnections of the shift register are modified, and/or an extra stage B5 inserted at the register input, to provide an input/output correspondence as indicated in table 1 (not shown).
GB23457/75A 1975-05-29 1975-05-29 Digital attenuator Expired GB1528954A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB23457/75A GB1528954A (en) 1975-05-29 1975-05-29 Digital attenuator
NL7605703A NL7605703A (en) 1975-05-29 1976-05-26 DIGITAL ATTENUATOR.
SE7606014A SE7606014L (en) 1975-05-29 1976-05-26 DIGITAL DAMPING CIRCUIT
FR7616180A FR2312883A1 (en) 1975-05-29 1976-05-28 DIGITAL ATTENUATOR, ESPECIALLY FOR COMPRESSED SIGNALS IN MODULATION BY CODE PULSES
DE19762624257 DE2624257A1 (en) 1975-05-29 1976-05-29 DIGITAL DAMPING ARRANGEMENT

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB23457/75A GB1528954A (en) 1975-05-29 1975-05-29 Digital attenuator

Publications (1)

Publication Number Publication Date
GB1528954A true GB1528954A (en) 1978-10-18

Family

ID=10195942

Family Applications (1)

Application Number Title Priority Date Filing Date
GB23457/75A Expired GB1528954A (en) 1975-05-29 1975-05-29 Digital attenuator

Country Status (5)

Country Link
DE (1) DE2624257A1 (en)
FR (1) FR2312883A1 (en)
GB (1) GB1528954A (en)
NL (1) NL7605703A (en)
SE (1) SE7606014L (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007025561A1 (en) * 2005-09-01 2007-03-08 Telefonaktiebolaget Lm Ericsson (Publ) Processing encoded real-time data

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4454498A (en) * 1979-05-21 1984-06-12 Siemens Aktiengesellschaft Adjustable attenuation member for a digital telecommunications system
DE3232548A1 (en) * 1982-09-01 1984-03-01 Siemens AG, 1000 Berlin und 8000 München METHOD AND CIRCUIT FOR TRANSCODING CODE WORDS

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3688097A (en) * 1970-05-20 1972-08-29 Bell Telephone Labor Inc Digital attenuator for non-linear pulse code modulation signals
US3781821A (en) * 1972-06-02 1973-12-25 Ibm Selective shift register

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007025561A1 (en) * 2005-09-01 2007-03-08 Telefonaktiebolaget Lm Ericsson (Publ) Processing encoded real-time data
US7804836B2 (en) 2005-09-01 2010-09-28 Telefonaktiebolaget L M Ericsson (Publ) Processing encoded real-time data
CN101268506B (en) * 2005-09-01 2011-08-03 艾利森电话股份有限公司 Processing code real-time data

Also Published As

Publication number Publication date
FR2312883A1 (en) 1976-12-24
NL7605703A (en) 1976-12-01
DE2624257A1 (en) 1976-12-09
SE7606014L (en) 1976-11-30

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Legal Events

Date Code Title Description
PS Patent sealed
746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee