Patent attributes
A transmission circuit includes a power amplifier, a power amplifier forestage circuit and a signal strength adjusting circuit. The power amplifier is configured to amplify an input signal to output an output signal. The power amplifier forestage circuit is configured to output the input signal. The signal strength adjusting circuit includes a conversion circuit, a processing circuit and a storage unit. The conversion circuit is configured to convert the voltage of the output signal into an operation value. The processing circuit is configured to perform an operation according to a target index value stored by the storage unit and the operation value to obtain a differential value. The processing circuit is further configured to adjust the input signal outputted by the power amplifier forestage circuit according to the differential value, so that the power of the output signal is maintained at a target power value.