Method and apparatus for decoding diphase signals
US3982195A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 1975 |
| Grant date | Sep 21, 1976 |
| Priority date | — |
| Expiry date | May 29, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/4904
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An incoming diphase signal is edge detected producing a train of pulses each pulse of which corresponds to a base-bit level transition or a mid-bit level transition. The mid-bit transition pulses are removed and the remaining base-bit transition pulses are used to control the frequency of a voltage controlled oscillator which clocks a shift register counter. Selected states of the counter are decoded to generate two regular pulse trains. Each pulse of the first pulse train occurs during the first half of a corresponding diphase base-bit time interval and the related pulse is used to selectively sample the diphase level. An exclusive NOR-gate compares this sampled level with the diphase level during the last half of the related diphase base bit time interval. The second train of pulses directs the sampling of the output of the exclusive NOR-gate at a selected moment during the last half of the same base-bit interval and the comparison information is stored for one base-bit interval thus generating a mark-space data signal corresponding to the data information carried by the incoming diphase signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.