A communication receiver system for receiving coded signals and of the type having at least one predetermined intermediate frequency (IF) signal comprising a decoder for detecting and decoding the received coded signals and a DC/DC voltage converter circuit, connected to the decoder, for generating a voltage greater than the supply voltage of the communication receiver system at a frequency below the frequency of the IF signal. The system further comprises a frequency trim circuit, connected to the voltage converter circuit, for controlling the operating frequency of the DC/DC voltage converter circuit whereby interference with the IF signal is prevented.