Amplifier provided at output stage of intermediate frequency amplifying circuit of mobile communication system
US5339460A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 13, 1992 |
| Grant date | Aug 16, 1994 |
| Priority date | — |
| Expiry date | Oct 13, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In a mobile communication system wherein only the circuits necessary for detecting a call send or a call receive operation are activated intermittently to reduce power consumption from a battery during a stand-by period, and all of the circuits are continuously activated by being supplied with power during a call operation, an amplifier is provided at an output stage of an intermediate frequency amplifying circuit in the system. The amplifier has an output transistor whose output terminal is connected to a load circuit via a capacitor, a circuit for supplying an operating direct current to the output transistor and a semiconductor switch provided in the current supply circuit. When the semiconductor switch is cut off, a leakage current flows through the output transistor, so that an average direct current voltage level is generated at the output terminal of the transistor. Accordingly, when the semiconductor switch is turned ON, the average direct current voltage level at the load circuit is obtained at high speed, and the rise time characteristics of the load circuit are improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.