A new scheme of a two-frequency radiation source based on a gyroklystron amplifier operating in the self-excitation mode and controlled by the input signal is proposed. Using a powerful 3-mm gyroklystron as an example, it is shown that, when operating in the beat mode (i.e., outside the synchronization band), by varying the frequency and power level of the input signal, it is possible to implement continuous independent tuning of the distance between spectral components in the 10-150 MHz range. and the ratio of their amplitudes in the range from -10 to 0 dB.