Noise blanking circuitry in a radio receiver
US4334317A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 13, 1980 |
| Grant date | Jun 8, 1982 |
| Priority date | — |
| Expiry date | Mar 13, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/345
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A radio receiver including an RF amplifier stage arranged to receive transmitted RF signals and noise signals from an antenna, a mixer stage for converting the RF signals to intermediate frequency (IF) signals and supplying the IF signals to a blanker gate receiving blanking signals from a blanking signal source, the gate normally passing IF signals to discriminator means to demodulate the IF signals to audio signals, but decoupling the mixer stage from the demodulator when the blanking signal is present. The audio signal output from the discriminator is applied to a noise squelch circuit which detects noise frequencies above a predetermined frequency. If the predetermined frequency is exceeded, a squelch signal is generated to block or mute the audio signals. In the present invention, the squelch circuit employs an averaging detector instead of a peak detector in order to eliminate short duration spikes in the squelch circuit. The blanking signal generator circuit employs a tracking pulse detector which is immune to false triggering by maintaining the detector threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.