Automatic gain control circuit of radio receiver
US5999578A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 21, 1997 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Apr 21, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/3078
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An automatic gain control circuit which is digitally embodied to prevent deterioration of bit error rate generated by saturation of a low noise amplifier located at the front stage of a receiver through an input of high power to an antenna, thereby simplifying construction thereof and improving commercialization. The automatic gain control circuit of a radio data communication system using a spread spectrum method utilizes a low noise amplifier for low noise amplifying a bandpass filtered signal received through an antenna; a limiter for generating a received signal strength indicator voltage in order to constantly maintain the signal received as a local oscillation frequency through the antenna before downward frequency conversion; a unit for separating the a signal transmitted through the limiter to I and Q channels; a comparator for comparing the received signal strength indicator voltage with a given reference voltage; a D flip-flop for inputting an output of the comparator applied to a data input terminal in synchronization to a given first control signal; an AND gate for ANDing the output of the D flip-flop and the first control signal; a field effect transistor having a gate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.