The receive part is designed for a double-conversion architecture. The incoming radio-frequency signal will be filtered and amplified before reaching the first mixer. At this stage, the RF signal will be converted down to the first intermediate frequency (10.7 MHz) by using a local adjustable oscillator (VCO3). The frequency of this oscillator is controlled by the PLL. The transmitter part contains two PLL-controlled VCOs. The frequency modulation is accomplished by superposing the incoming audio signal on the first PLL control voltage. In this system, the frequency is a product of mixing VCO1 with local oscillator (VCO3). The FMmodulated carrier is amplified by external power amplifier before entering the output filter and the antenna connector.