Patent US3008484A successfully refreshed from Google Patents.
Patent US4023608A successfully refreshed from Google Patents.
Patent CA1161973A successfully refreshed from Google Patents.
CA1161973A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Level control of digital signals
Assignee: STC PLC
•
Filing: 1979-02-21
•
Granted: 1984-02-07
•
Expires: 1999-02-21
Abstract
Abstract ABSTRACT A digital level control for varying the level of a linearly digitally encoded analogue signal. The linear pcm signal is digitally filtered to pro-vide an external gain control via a digital multiplier of the pcm signal. The arrangement may be time shared between a number of channels to provide control on a per call basis to compensate for variations which occur in the course of cabling, switching and maintenance of transmission signal quality.
Inventors
- 👤 Michael J. Gingell
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-10-30 21:04
CPC Classifications
—
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
210 words
A subscriber carrier system for a plurality of time multiplexed communications channels, each of said channels being capable of transmitting a plurality of n-bit digital words, having a digital level control for provid-ing a selective gain of attenuation of said n-bit digital words, comprising: analog to digital conversion means for converting analog input sig-nals in a communication channel into said n-bit digital words, such that said n-bit digital words are linearly related to said analog input signals; digital filter means having said n-bit words serially coupled thereto for filtering said n-bit digital words and for digitally multiplying said n-bit words with weighting coefficients, wherein said digital filter means com-prises: first digital filter means for low pass filtering said n-bit digital words; and second digital filter means for high pass filtering said n-bit digital words; digital level control means for varying at least some of said co-efficients to maintain a predetermined transmission level of said n-bit digital words; multiplexing means; for time multiplexing said plurality of n-bit digital words from said plurality of communications channels into a serial data stream; and means for coupling said time multiplexed data stream to said digital level control means such that said digital level control means is time shared by said plurality of communication channels.
Claim 2
Dependent Claim
210 words
A subscriber carrier system for a plurality of time multiplexed communications channels, each of said channels being capable of transmitting a plurality of n-bit digital words, having a digital level control for provid-ing a selective gain of attenuation of said n-bit digital words, comprising: analog to digital conversion means for converting analog input sig-nals in a communication channel into said n-bit digital words, such that said n-bit digital words are linearly related to said analog input signals; digital filter means having said n-bit words serially coupled thereto for filtering said n-bit digital words and for digitally multiplying said n-bit words with weighting coefficients, wherein said digital filter means com-prises: first digital filter means for low pass filtering said n-bit digital words; and second digital filter means for high pass filtering said n-bit digital words; digital level control means for varying at least some of said co-efficients to maintain a predetermined transmission level of said n-bit digital words; multiplexing means; for time multiplexing said plurality of n-bit digital words from said plurality of communications channels into a serial data stream; and means for coupling said time multiplexed data stream to said digital level control means such that said digital level control means is time shared by said plurality of communication channels.
Claim 3
Dependent Claim
75 words
A subscriber system in accordance with claim 1, wherein said high pass filter means includes means for serially receiving said low pass filter-ed n-bit digital words and for digitally multiplying said digital words in parallel with weighting coefficients, at least some of which weighting co-efficients are fixed and some of which weighting coefficients are variable; and control means for varying said variable coefficients to effect a pre-determined gain or attenuation of said n-bit digital words.
Claim 4
Dependent Claim
38 words
A subscriber system in accordance with claim 2, wherein said control means includes: a matrix of said weighting coefficients; memory means associa-ted with said matrix for varying said variable coefficients in accordance with information stored in said memory.
Claim 5
Dependent Claim
24 words
A subscriber system in accordance with claim 3, wherein said control means includes means for addressing said memory means to select said variable coefficients.
Claim 6
Dependent Claim
44 words
A subscriber carrier system, in accordance with claim 4, wherein said analog to digital conversion means includes: means for converting said analog input signals into a pulse density modulated code; and means for converting said pulse density modulated code into said n-bit digital words.
Claim 7
Dependent Claim
39 words
A subscriber carrier system in accordance with claim 5, further com-prising: pulse compression means for translating said n-bit digital words multiplied by said weighting coefficients into compressed PCM; and means for transmitting said compressed PCM onto a transmission line.
Claim 8
Dependent Claim
100 words
A subscriber carrier system, in accordance with claim 6 further com-prising: receiving means for receiving said compressed PCM from said transmis-sion line, said receiving means comprising: means for converting said compres-sed PCM to linear PCM n-bit words; digital level control means for selectively and controllably weighting at least some of the data bits of said n-bit words, and having an output; demultiplexing means for deriving a plurality of digital data channels from said output of said digital level control means; and digital to analog conversion means for convert-ing said demultiplexed data in each of said data channels into analog signals.
Claim 9
Dependent Claim
44 words
A subscriber carrier system in accordance with claim 7 wherein said digital to analog conversion means includes: means for converting said linear PCM n-bit words into a pulse density modulated code; and means for converting said pulse density modulated code into said analog signals.
Claim 10
Dependent Claim
179 words
A telephone trunk system for a plurality of time multi-plexed communications channels, each of said channels being capable of transmitting a plurality of n-bit digital words, having a digital level control for providing a selective gain or attenuation of said n-bit digital words, comprising: analog to digital conversion means for converting analog input signals in a communication channel into said n-bit digital words, such that said n-bit digital words are linearly related to said analog input signals; digital filter means having said n-bit words serially coupled thereto for filtering said n-bit digital words and for digitally multiplying said n-bit words with weighting coefficients; digital level control means for varying at least some of said coefficients to maintain a predetermined transmission level of said n-bit digital words; multiplexing means for time multiplexing said plurality of n-bit digital words from said plurality of communications channels into a serial data stream; and means for coupling said time multiplexed data stream to said digital level control means such that said digital level control means is time shared by said plurality of communications channels.
Claim 11
Dependent Claim
179 words
A telephone trunk system for a plurality of time multi-plexed communications channels, each of said channels being capable of transmitting a plurality of n-bit digital words, having a digital level control for providing a selective gain or attenuation of said n-bit digital words, comprising: analog to digital conversion means for converting analog input signals in a communication channel into said n-bit digital words, such that said n-bit digital words are linearly related to said analog input signals; digital filter means having said n-bit words serially coupled thereto for filtering said n-bit digital words and for digitally multiplying said n-bit words with weighting coefficients; digital level control means for varying at least some of said coefficients to maintain a predetermined transmission level of said n-bit digital words; multiplexing means for time multiplexing said plurality of n-bit digital words from said plurality of communications channels into a serial data stream; and means for coupling said time multiplexed data stream to said digital level control means such that said digital level control means is time shared by said plurality of communications channels.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.