Mobile telephone frequency generating circuit includes two oscillators under control from coefficient table to produced required output

摘要

The telephone includes a lookup table of coefficients to control frequency generation. The mobile telephone includes a transmission circuit including combined oscillation circuits (4,5). The first oscillation circuit (4) produces an FRF transition frequency, the second oscillation circuit (5) produces an F1 intermediate frequency. The transition frequency and the intermediate frequency differ by a frequency, FTX, which is the transmission frequency. A table of coefficients (U,V) is stored for a given transmission frequency, each coefficient being transformed into a signal which is applied to a control input of the oscillation circuit. This enables control of the parasitic signals produced, in order to provide the required output transmission frequency signal without corruption from parasitic signals.