Automatic level control circuit for dual mode analog/digital cellular telephone
US5438683A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 1994 |
| Grant date | Aug 1, 1995 |
| Priority date | — |
| Expiry date | Sep 19, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/3047
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An automatic level control circuit for cellular telephone transmitters which is compatible with both existing analog cellular service and expected next generation digital TDMA service. The circuit automatically and dynamically changes modes to maintain communication when a mobile subscriber moves from one type of service to another. In a first mode of operation, which is compatible with existing analog cellular service, the circuit provides a closed loop negative feedback circuit which produces a control signal for continuously controlling the output power level of the transmitter amplifier. In a second mode of operation, which is compatible with proposed digital TDMA service, the circuit operates to alternately close the negative feedback loop during the periods when the transmitter is permitted to transmit (assigned TDMA frames) and open the loop during other periods when the transmitter is turned off. When the loop is opened, the invention temporarily stores the magnitude of the control signal. This stored value is subsequently used to quickly restore the amplifier to its assigned power level during successive frames when the loop is again closed for burst transmission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.