Apparatus for testing the linearity of a frequency modulated oscillator
US4399408A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1981 |
| Grant date | Aug 16, 1983 |
| Priority date | — |
| Expiry date | Mar 2, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/2824
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An APC (automatic phase control) circuit is utilized to measure the linearity of an FMO (frequency modulated oscillator). In accordance with a common APC concept a programmable divider is connected to an output of said frequency modulatable oscillator to produce a binary output signal having a predetermined pulse repetition rate. This signal is compared with a reference oscillator signal in a phase control comparator producing a DC control signal which is applied to the control input of said frequency modulated oscillator to maintain the average oscillator frequency constant. This DC control voltage gives an indication of average free running frequency of the oscillator. To measure linearity, the said binary signal at the programmable divider output is also further divided and processed to produce a low frequency square waveform which is applied via a manual ON/OFF switch and a modulation amplifier to the modulation input of the said FMO. The change in the average free running frequency of the FMO, and the corresponding change in the DC control voltage resulting from alternatively switching the low frequency waveform ON and OFF, is a measure of the FMO's linearity. This change is a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.