Frequency control circuits such as for use in modulation measurement
US3992670A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1975 |
| Grant date | Nov 16, 1976 |
| Priority date | — |
| Expiry date | Apr 3, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R23/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A circuit responsive to an input signal having an unspecified frequency for converting it to a predetermined and constant means frequency, and particularly suitable for incorporation in a modulation measuring instrument, comprises a sampling mixer controlled by a variable frequency oscillator for sampling the input signal to produce an intermediate signal. The mean frequency of the intermediate signal is then compared with a reference representing a predetermined frequency value whereby to produce an error signal, and means responsive to the error signal adjusts the frequency of the oscillator in such a direction as to tend to hold the mean value of the frequency of the intermediate signal at the predetermined frequency value while preserving therein variations in amplitude and/or frequency due to amplitude and/or frequency modulation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.