GB849891A - Improvements in or relating to electric pulse code modulation systems of communication - Google Patents
Improvements in or relating to electric pulse code modulation systems of communicationInfo
- Publication number
- GB849891A GB849891A GB1190558A GB1190558A GB849891A GB 849891 A GB849891 A GB 849891A GB 1190558 A GB1190558 A GB 1190558A GB 1190558 A GB1190558 A GB 1190558A GB 849891 A GB849891 A GB 849891A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pulses
- digit
- code
- pulse
- group
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
- H04L25/40—Transmitting circuits; Receiving circuits
- H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
- H04L25/4906—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems using binary codes
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/80—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using non-linear magnetic devices; using non-linear dielectric devices
- H03K17/82—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using non-linear magnetic devices; using non-linear dielectric devices the devices being transfluxors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K23/00—Pulse counters comprising counting chains; Frequency dividers comprising counting chains
- H03K23/76—Pulse counters comprising counting chains; Frequency dividers comprising counting chains using magnetic cores or ferro-electric capacitors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
- H03K3/45—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of non-linear magnetic or dielectric devices
-
- 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
- H03M1/36—Analogue value compared with reference values simultaneously only, i.e. parallel type
- H03M1/361—Analogue value compared with reference values simultaneously only, i.e. parallel type having a separate comparator and reference value for each quantisation level, i.e. full flash converter type
- H03M1/362—Analogue value compared with reference values simultaneously only, i.e. parallel type having a separate comparator and reference value for each quantisation level, i.e. full flash converter type the reference values being generated by a resistive voltage divider
- H03M1/365—Analogue value compared with reference values simultaneously only, i.e. parallel type having a separate comparator and reference value for each quantisation level, i.e. full flash converter type the reference values being generated by a resistive voltage divider the voltage divider being a single resistor string
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M5/00—Conversion of the form of the representation of individual digits
-
- 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
- H03M7/14—Conversion to or from non-weighted codes
- H03M7/16—Conversion to or from unit-distance codes, e.g. Gray code, reflected binary code
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M9/00—Parallel/series conversion or vice versa
-
- 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
- H04B14/042—Special circuits, e.g. comparators
-
- 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
- H04B14/044—Sample and hold circuits
-
- 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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Nonlinear Science (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Power Engineering (AREA)
- Dc Digital Transmission (AREA)
Abstract
849,891. Pulse code modulation systems. STANDARD TELEPHONES & CABLES Ltd. April 10, 1959 [April 15, 1958], No. 11905/58. Class 40(5). In a pulse code modulation system, the binary code employed is of the unit disparity, unit distance type i.e. one in which each code group has (2n - 1) digit positions of which either n or (n - 1) are occupied by pulses, the groups being so arranged that a signal amplitude charge of one level produces a charge in only one digit position. The code described with reference to Fig. 2 has the further property that the groups are arranged in such an order that the group representing any even numbered level can be obtained by adding together the groups representing the two adjacent odd numbered levels and limiting the pulses to the same amplitude. As a result the number of coding elements necessary can be almost halved without reducing the coding speed. Not all the possible combinations can be used in this code, the number N 1 used being equal to 2 x 3, (n-1). The 7-digit code of Fig. 2 has either three or four pulses in each group and may be converted to a balanced error-detecting code by the addition of a fourth pulse in the eighth digit position for all the odd numbered levels. The additional pulse takes no part in the actual coding of the signal and may be disregarded at the receiver. If n is not too small, error detecting means may be provided to determine whether each group contains either n or n - 1 pulses, and the additional pulse is not necessary. A coder for producing the 5-digit code represented in the portion of Fig. 2 bounded by the lines A, B is shown in Fig. 3 and comprises ten coding elements 101 representing odd numbered levels 1-17 and the highest level, 18. Each coding element is biased by tappings on potential divider 107 fed by a positive source 103 and a negative source 104. Pulses from source 111 control a sampler 109 and read pulse generator 112, the pulses from sampler 109 being arranged to gate the coding elements 101 in the following manner. When the sampled signal corresponds to an odd numbered level or level 18, only the coding element corresponding to that level is unblocked, all other elements 101 being blocked, but when the sampled signal corresponds to an even numbered level, other than level 18, the two corresponding adjacent odd numbered coding elements are unblocked. A reading pulse from generator 112 after passing through limiting circuit 113 and valve 114 is only passed by the one or two unblocked coding elements. The horizontal output conductor of each coding element is connected to the appropriate vertical digit conductors 1-5 by a rectifier matrix to produce the correct code group simultaneously on the five digit conductors, which conductors are connected to tappings on a delay net 117 to produce the code group in serial form at output terminal 119. In the case of an even numbered level e.g. level 10, coding elements for levels 9, 11 are unblocked and the two output code groups are combined in digit conductors 1-5, the limiting circuit 120, 121 maintaining the correct digit pulse amplitude. Means, Figs. 6, 7 (not shown) may be provided to detect the presence of only two pulses in any code group and to add a third pulse in the sixth digit position. The receiver shown in Fig. 8 is for an 8-digit balanced error-detecting code in which each group should contain four pulses. The decoder 144 is of the type having eight output conductors 145 corresponding to the eight digit positions, positive output pulses being produced on those output conductors corresponding to the digit positions in which the digit pulses of a group occur, and negative pulses being produced on the remaining output conductors. Error detector 147 produces an output pulse whenever the combination of pulses simultaneously fed into it is other than four positive and four negative. Synchronizing. Filter 148 and divider 149 provide synchronizing pulses at the group repetition frequency, these pulses being fed through adjustable delay device 150 to control decoder 144. When synchronism is lost, a group selected by decoder 144 will contain either more or less than four pulses, the output pulse produced by detector 147 operating alarm 151 and stepping delay device 150 by one digit period. This process is repeated until synchronism is regained. Synchronism may alternatively be obtained by transmitting one of the unused code groups or preferably by transmitting the groups 11110000, 00001111 in sequence. These synchronizing groups may also be used for channel synchronizing in a multiplex system.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1190558A GB849891A (en) | 1958-04-15 | 1958-04-15 | Improvements in or relating to electric pulse code modulation systems of communication |
CH7220159A CH374719A (en) | 1958-04-15 | 1959-04-14 | Electrical pulse code modulation system for telecommunications |
DE1959I0016285 DE1171002B (en) | 1958-04-15 | 1959-04-14 | PCM communication system |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1190558A GB849891A (en) | 1958-04-15 | 1958-04-15 | Improvements in or relating to electric pulse code modulation systems of communication |
GB3393258A GB857736A (en) | 1958-11-14 | 1958-10-23 | Improvements in or relating to magnetic trigger devices |
GB3670558A GB840023A (en) | 1958-11-14 | 1958-11-14 | Improvements in or relating to magnetic information storage devices |
Publications (1)
Publication Number | Publication Date |
---|---|
GB849891A true GB849891A (en) | 1960-09-28 |
Family
ID=32475018
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1190558A Expired GB849891A (en) | 1958-04-15 | 1958-04-15 | Improvements in or relating to electric pulse code modulation systems of communication |
Country Status (2)
Country | Link |
---|---|
CH (1) | CH374719A (en) |
GB (1) | GB849891A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3144605A (en) * | 1956-09-14 | 1964-08-11 | Int Standard Electric Corp | Communication repeater employing the pulse-code modulation method and comprising fault-alarm means |
EP0135290A2 (en) * | 1983-08-22 | 1985-03-27 | Trw Inc. | Analog-to-digital-converter and related encoding technique |
CN113176451A (en) * | 2021-04-22 | 2021-07-27 | 浙江威星智能仪表股份有限公司 | Pulse signal detection method based on table look-up method |
-
1958
- 1958-04-15 GB GB1190558A patent/GB849891A/en not_active Expired
-
1959
- 1959-04-14 CH CH7220159A patent/CH374719A/en unknown
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3144605A (en) * | 1956-09-14 | 1964-08-11 | Int Standard Electric Corp | Communication repeater employing the pulse-code modulation method and comprising fault-alarm means |
EP0135290A2 (en) * | 1983-08-22 | 1985-03-27 | Trw Inc. | Analog-to-digital-converter and related encoding technique |
EP0135290A3 (en) * | 1983-08-22 | 1988-06-22 | Trw Inc. | Analog-to-digital-converter and related encoding technique |
CN113176451A (en) * | 2021-04-22 | 2021-07-27 | 浙江威星智能仪表股份有限公司 | Pulse signal detection method based on table look-up method |
CN113176451B (en) * | 2021-04-22 | 2023-08-15 | 浙江威星智能仪表股份有限公司 | Pulse signal detection method based on table look-up method |
Also Published As
Publication number | Publication date |
---|---|
CH374719A (en) | 1964-01-31 |
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