Method and circuitry for demodulation of angle modulated signals by measuring cycle time
US5270666A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1992 |
| Grant date | Dec 14, 1993 |
| Priority date | — |
| Expiry date | Jul 16, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/60
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An FM or PM signal is demodulated so that the cycle time of the modulated input signal is measured using a time-to-digital converter comprising a counter that uses a moderate clock frequency as a reference clock, a digital delay line interpolator and a control circuitry. The counter is used for rough digitization and the delay line for interpolating the moment of zero-crossing inside a clock cycle. Total delay of the delay line, i.e., the range of time intervals the interpolator is able to measure, is actively kept equal to the cycle time of the reference clock. When the number of delay elements in the delay line is a power of two, the result of the delay line interpolator may be used directly as the least significant bits of the measurement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.