Pulse or digital communications – Repeaters – Testing
Patent
1979-08-24
1982-09-07
Sloyan, Thomas J.
Pulse or digital communications
Repeaters
Testing
340347C, 340347M, 340347AD, 340347DA, H03K 1302
Patent
active
043487688
ABSTRACT:
A codec (coder/decoder), having particular utility in a pulse code modulation (PCM) communications system employing per-line coding and decoding, employs a common digital-to-analog (DAC) converter. A PCM signal to be reconstructed is decoded at two points of time within the basic sampling interval, preferably at twice the basic sampling frequency. In order to realize the desired analog reconstruction level, the PCM signal is first decoded at a first decision level lying on one side of the desired reconstruction level; then modified and again decoded at a different decision level lying on the other side of the desired reconstruction level. The average of the two decoded analog signals then lies on the desired reconstruction level. In a conventional PCM system, the two PCM samples differ by only one least significant bit (LSB) in the PCM word used in setting the common DAC. In a preferred embodiment of the invention, separate storage registers are respectively employed for the encoding and decoding, together with a selector for switching between the two registers during the two desired decoding intervals. In this way, the encoding operation may be carried on during a substantial portion of the basic sampling cycle, being interrupted only for generation of decoded samples. The invention is applicable to PCM systems generally, including compressed pulse code modulation (CPCM) systems operating in accordance with the U-law or the A-law.
REFERENCES:
patent: 3656152 (1972-04-01), Gundersen
patent: 3879724 (1975-04-01), McDonald
patent: 3883864 (1975-05-01), Thomas
patent: 3893102 (1975-07-01), Candy
patent: 3900844 (1975-08-01), Wald
patent: 3906489 (1975-09-01), Schlichte
patent: 3984829 (1976-10-01), Zwack
patent: 3993992 (1976-11-01), Zwack
patent: 4056820 (1977-11-01), Hofer
patent: 4151518 (1979-04-01), Jansson et al.
patent: 4160243 (1979-07-01), Moriya et al.
Apon et al., Comcon, An Educational Project-, Paper presented at ISS 1974 in 9/74.
International Telephone and Telegraph Corporation
Lenkszus Donald J.
Raden James B.
Sloyan Thomas J.
LandOfFree
PCM Codec using common D/A converter for encoding and decoding does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with PCM Codec using common D/A converter for encoding and decoding, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and PCM Codec using common D/A converter for encoding and decoding will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1345796