The RF-oscillator is available at pins 3 - 7. The oscillator operates as a symmetrical Colpitts circuit. The oscillator chip ground, pin 5, should be connected to ground at the resonance circuit shielding point. An external oscillator can be injected inductively or capacitively via pins 3 and 7. The layout of the PCB should be such as to provide a minimum shielding attenuation between the oscillator pins 3 - 7 and modulator output pins 15 - 17 of approximately 80 dB. Semiconductor Group