Optimal radio frequency receiver
US5732342A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1996 |
| Grant date | Mar 24, 1998 |
| Priority date | — |
| Expiry date | Jun 21, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/50
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A radio-frequency (RF) receiver generally contains an RF amplifier, a mixer stage, a mixer oscillator, a demodulator and an AGC (automatic gain control) circuit, to which the output voltage of the demodulator and a set voltage value for the automatic gain control are applied. Such RF receivers have a non-optimal signal-to-noise ratio under certain circumstances. The present invention improves the signal-to-noise ratio in such high frequency receivers, as well as the effectiveness of the AFT (automatic fine tuning) circuit. The amplitude of the AGC set voltage value is regulated depending on the frequency of the received RF signal so that the mixer stage is optimally controlled at all frequencies of the RF signal. In one embodiment, a PLL circuit connected to the output of the intermediate frequency amplifier to regenerate the non-modulated image carrier, is further used to ensure automatic fine tuning by regulating the frequency of the mixer oscillator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.