Local oscillators for radio receivers
US4921467A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 31, 1988 |
| Grant date | May 1, 1990 |
| Priority date | — |
| Expiry date | May 31, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J7/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A local oscillator for a radio receiver includes a voltage controlled oscillator (VCO), a decoder and controller for providing a control voltage to the VCO, an error detector circuit for detecting an error in the frequency of the VCO on the basis of a received signal processed with the oscillating signal from the VCO, a temperature probe and a memory. The local oscillator is initially set up during manufacture by detecting any errors in the frequency at selected temperatures, and storing data in the memory indicative of the control voltage required to compensate for the frequency error for each temperature. In operation the decoder and controller applies the appropriate control voltage to the VCO on the basis of the data stored in the memory relative to the temperature detected by the temperature probe. If, for example as a result of ageing of the oscillator, the error detector detects an error in the frequency, the decoder and controller adjusts the control voltage to the VCO so as to compensate for the error, and the updated value is stored in the memory for subsequent use. If the received signal is mixed with the oscillating signal in a mixer, the output of intermediate frequenc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.