GB1187688A - Digital Data Receiver - Google Patents
Digital Data ReceiverInfo
- Publication number
- GB1187688A GB1187688A GB4797568A GB4797568A GB1187688A GB 1187688 A GB1187688 A GB 1187688A GB 4797568 A GB4797568 A GB 4797568A GB 4797568 A GB4797568 A GB 4797568A GB 1187688 A GB1187688 A GB 1187688A
- Authority
- GB
- United Kingdom
- Prior art keywords
- gate
- signal
- pulses
- zero
- delay
- 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
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0054—Detection of the synchronisation error by features other than the received signal transition
- H04L7/0062—Detection of the synchronisation error by features other than the received signal transition detection of error based on data decision error, e.g. Mueller type detection
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
- H04L7/027—Speed or phase control by the received code signals, the signals containing no special synchronisation information extracting the synchronising or clock signal from the received signal spectrum, e.g. by using a resonant or bandpass circuit
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0054—Detection of the synchronisation error by features other than the received signal transition
- H04L7/0066—Detection of the synchronisation error by features other than the received signal transition detection of error based on transmission code rule
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
- Manipulation Of Pulses (AREA)
Abstract
1,187,688. Digital transmission systems. INTERNATIONAL BUSINESS MACHINES CORP. 10 Oct., 1968 [8 Nov., 1967; 9 Nov., 1967; 8 Dec., 1967], No. 47975/68. Heading H4P. Synchronizing signals are derived from a signal which has digital data signals at times tn, t<SP>1</SP>n and non-significant signals at all other times. Whenever the signal has a preset amplitude a sync. pulse is generated. This amplitude occurs at tn, t<SP>1</SP>n and may also occur at other times. The receiver prevents sync. pulses occurring at times other than tn, t<SP>1</SP>n from effecting the oscillator. In one embodiment, the received signal contains binary data and passes to a subtraction unit S, Fig. 3, via rectifiers 31, 32 and delay 33 whose period t = t<SP>1</SP>n-tn. The output of S is a signal which has zero amplitude whenever the preset amplitude is detected, and is passed via monostables SS1, SS2 and inverter I1 to OR gate 01 which gives pulses p whenever the output of S is zero. Gate 01 feeds oscillator Plo which clock pulses of period T, T being the recurrence period of both tn and t<SP>1</SP>n. Gate A1 is inhibited by the output of monostable SS3, fed by the clock pulses, so that any sync. pulses occurring at times other than tn, t<SP>1</SP>n cannot reach Plo. During unitial synchronization, when a special start signal is received, a signal on Dem maintains A1 enabled. In a second embodiment, Fig. 5 (not shown), the digital signals may take any of four preset valves. Rectifiers 31, 32, Fig. 3, are additionally connected to two weighted subtraction units whose outputs pass to an EXCL-OR gate which feeds a second EXCL-OR gate inserted between S and SQ: Another arrangement, Fig. 6, in which there is no initial sync. signal, uses a series of delay units, each of period T, to which the rectified received signal is fed. An AND gate, A3 is fed as shown and emits a pulse about the times tn, t<SP>1</SP>n, Fig. 2b (not shown), since at other times at least one input to the gate is likely to be zero. The output of the gate is used to gate appropriate pulses of signal p to the oscillator. Alternatively, Fig. 7 (not shown), the delays may be replaced by a single delay T fed via an AND gate with the rectified signal, the delay giving synchronizing pulses which are also fed back to the gate. The delay may comprise a shift register, and a threshold unit may precede the AND gate, Fig. 8 (not shown). In another embodiment, Fig. 11, there is a unit 111 generally similar to Fig. 3, and in addition a weighted adder 112 and a unit 113 containing an adder, a delay, and a subtractor. The outputs of both 112 and 113 are zero only about tn, t<SP>1</SP>n, and are fed to analog adder AD3 together with the clock signal from PL0. The resulting signal c is zero at times t<SP>1</SP>n and attenuates the unwanted pulses from 111, the wanted pulses synchronizing the oscillator PL0. Where 4-level signals are received, Fig. 13 (not shown), units 112, 113, Fig. 11, are replaced by weighted adders Ad4, Ad5, the lesser of the two outputs passing to the gate Ad3. In a final embodiment, Fig. 15, the received signal is fed direct and via a delay t to a unit 151, which outputs the lesser of the two signals. This output passes to capacitor C1 to Cn, switched in sequentially for a period T/n by unit Seq. A capacitor charges slowly when switched in unless the output of 151 is zero, when the capacitor rapidly discharges. Since 151 gives zero output at random, but never at the times t<SP>1</SP>n, after several periods T one capacitor will have a charge higher than the others, so identifying the time t<SP>1</SP>n.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR06008819 | 1967-11-08 | ||
FR06008820 | 1967-11-09 | ||
FR06008899 | 1967-12-08 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1187688A true GB1187688A (en) | 1970-04-15 |
Family
ID=27249049
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB4797568A Expired GB1187688A (en) | 1967-11-08 | 1968-10-10 | Digital Data Receiver |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1187688A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2143096A (en) * | 1983-07-06 | 1985-01-30 | Motorola Israel Ltd | Clock recovery circuit |
-
1968
- 1968-10-10 GB GB4797568A patent/GB1187688A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2143096A (en) * | 1983-07-06 | 1985-01-30 | Motorola Israel Ltd | Clock recovery circuit |
Also Published As
Publication number | Publication date |
---|---|
DE1807363B2 (en) | 1972-10-19 |
DE1807363A1 (en) | 1969-09-11 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |