Method and circuit for a fast reduction in voltage of a DC component and low-frequency components at a mixing circuit output in a receiver of a UHF transceiver
US8315585B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Feb 13, 2009 |
| Grant date | Nov 20, 2012 |
| Priority date | — |
| Expiry date | Sep 1, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A difference between an output current signal (mos) of the mixing circuit (MC) and a current from a controlled current source (CCS) is conducted to an input of an operational amplifier (A). A control voltage (cv) for said current source is a voltage at the output of the operational amplifier (A) being filtered by a low-pass filter, whose limiting frequency equals a low frequency limit of the modulation signal in the received signal (rs). The method is speeded up in that the limiting frequency of the low-pass filter is increased by two to three orders of magnitude at the beginning and is gradually lowered to said value. A rather short time duration of the transient process is achieved so that the working point with a low voltage of the DC component and low-frequency components is set at least five times faster than so far.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.