TW-42 FM radio transmitter high-frequency amplifier circuit section
Posted on Dec 11, 2010 5209
FM radio transmitter is a high-frequency amplifier circuit. This circuit uses Mitsubishi frequency set successfully discharge path M57704H. Using radio frequency modulation, th
e operating frequency is 457-458MHz, transmit power is 5w. Seen from the figure, the input amplitude modulated signal through after M57704H power amplifier, all the way through a microstrip line matched filtering, and then after VT1 send a multi-section LC Ji-type network, and then transmitted by the antenna out; another path VD2, VD3 detection. VT2, VT3 After DC amplification, gave VT1 regulator, as the control voltage from M57704H feet first entered the first stage t adjust the power amplifier collector, can stabilize the entire integrated amplifier output power. The second three amplifier collector electrode power supply is fixed 13. 8V.