JPS54128644A - Clock selection circuit - Google Patents
Clock selection circuitInfo
- Publication number
- JPS54128644A JPS54128644A JP3722178A JP3722178A JPS54128644A JP S54128644 A JPS54128644 A JP S54128644A JP 3722178 A JP3722178 A JP 3722178A JP 3722178 A JP3722178 A JP 3722178A JP S54128644 A JPS54128644 A JP S54128644A
- Authority
- JP
- Japan
- Prior art keywords
- clock
- spare
- existing
- selection
- detection circuits
- 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.)
- Granted
Links
Landscapes
- Synchronisation In Digital Transmission Systems (AREA)
Abstract
PURPOSE: To prevent the phase variation at selection, by taking the time constant of monostable multivibrator detecting the open clock as within the specified condition.
CONSTITUTION: The existing and spare clock of bipolar type fed from rhe existing and spare digital clock supply units 41 and 42 are converted into the unipolar signal at the bipolar unipolar conversion circuits 6 and 7. The converted clock is given to the open detection circuits 80 and 90. The selection circuit 10 is controlled with the open detection circuits 80 and 90 and either of them is selected. The clock is inputted to the tuning circuit 11 and the output is given to the digital units 1,2. As the open detection circuits 80,90, the monostable multivibrator having edge trigger type so that the time constant Yd satisfies the equation -(2), is used. Where t is a half period of the clock, and n is an integer. As a result, the drive pulse to the circuit 11 when the unit is changed over from existing to spare, is on the same time series, and the phase variation is prevented for selection.
COPYRIGHT: (C)1979,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3722178A JPS54128644A (en) | 1978-03-29 | 1978-03-29 | Clock selection circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3722178A JPS54128644A (en) | 1978-03-29 | 1978-03-29 | Clock selection circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS54128644A true JPS54128644A (en) | 1979-10-05 |
JPS6148725B2 JPS6148725B2 (en) | 1986-10-25 |
Family
ID=12491525
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3722178A Granted JPS54128644A (en) | 1978-03-29 | 1978-03-29 | Clock selection circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS54128644A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63191434A (en) * | 1987-02-04 | 1988-08-08 | Nippon Telegr & Teleph Corp <Ntt> | Clock circuit |
JPH03165134A (en) * | 1989-11-24 | 1991-07-17 | Nec Corp | Clock selection switching system |
US5287010A (en) * | 1989-12-27 | 1994-02-15 | Masao Hagiwara | Device for preventing erroneous operation when the clock is interrupted in a controller |
-
1978
- 1978-03-29 JP JP3722178A patent/JPS54128644A/en active Granted
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63191434A (en) * | 1987-02-04 | 1988-08-08 | Nippon Telegr & Teleph Corp <Ntt> | Clock circuit |
JPH03165134A (en) * | 1989-11-24 | 1991-07-17 | Nec Corp | Clock selection switching system |
US5287010A (en) * | 1989-12-27 | 1994-02-15 | Masao Hagiwara | Device for preventing erroneous operation when the clock is interrupted in a controller |
Also Published As
Publication number | Publication date |
---|---|
JPS6148725B2 (en) | 1986-10-25 |
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