Transmitter/receiver apparatus with common oscillator that changes frequency between transmitting and received operations
US5239689A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 18, 1991 |
| Grant date | Aug 24, 1993 |
| Priority date | — |
| Expiry date | Oct 18, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/50
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A transmitter/receiver apparatus wherein a sufficiently great difference is assured between frequencies of intermediate frequency signals of transmitting and receiving circuits to assure an improved disturbance preventing performance. An oscillating circuit for oscillating a signal for selection of a channel is provided commonly for the transmitting and receiving circuits. In the transmitting circuit, power is supplied, also in a receiving operation, to a modulating circuit so that it continues a modulating operation, and an output of the modulating circuit is frequency converted with an oscillation output of the oscillating circuit into a signal of a frequency corresponding to a predetermined channel. In the receiving circuit, a received signal of the predetermined channel is frequency converted with the oscillation output of the oscillating circuit into a signal of an intermediate frequency. The frequency of the oscillation output of the oscillating circuit is varied by a predetermined amount between transmission and reception.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.