Phase noise measurements utilizing a frequency down conversion/multiplier, direct spectrum measurement technique
US5179344A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1991 |
| Grant date | Jan 12, 1993 |
| Priority date | — |
| Expiry date | Jun 21, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R29/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved circuit for phase noise measurements utilizing a frequency down conversion/multiplier and direct spectrum measurement technique which uses a combination of a phase detector method and a direct spectrum approach. The circuit is particularly useful for field test environments where laboratory instrumentation is normally not available, and fast and accurate phase noise measurements are required. The phase noise measuring circuit includes a frequency mixer which has a first input signal from a device under test and a second input signal from a reference stable oscillator having ultra low phase noise with a fixed center frequency. The frequency mixer mixes the first and second input signals to produce a down converted signal comprising the frequency difference signal of the first and second input signals. A lowpass filter then passes the down converted signal to a frequency doubler circuit which produces a doubled frequency, down converted signal. A lowpass signal filter then passes the doubled frequency, down converted signal to an amplifier. The output of the amplifier is directed to a second frequency doubler circuit which produces a quadrupled frequency, down converted s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.