Directly mixing receiving system
US4408351A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1980 |
| Grant date | Oct 4, 1983 |
| Priority date | — |
| Expiry date | Jan 25, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/30
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In a broadcast signal receiving system, which includes a phase control loop composed of a first mixer having two inputs and an output and arranged to provide at its output a signal proportional to the product of the signals applied to its two inputs, one output being supplied with the received high frequency signal, a voltage controlled oscillator connected for supplying to the other input of the first mixer an alternating voltage of substantially constant amplitude, a first lowpass filter connected to the output of the first mixer for providing a filtered output signal representative of the first mixer output signal with the sum frequency component of that signal suppressed, and means for delivering the output signal of the first low-pass filter to the control input of the oscillator, the received high frequency signal is directly demodulated by multiplication with a local oscillator signal synchronized to a substantially fixed difference to the phase or the carrier phase of the received high frequency signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.