| 摘要 |
The code transmitter has an oscillator circuit (1) whose resonant frequency can be varied by an impedance (3) which can be connected to it. A control unit controls an HF switch (2) via which the impedance is connected to the oscillator circuit depending on a control signal. The oscillator output signal is transmitted via a transmission antenna (L1). The HF switch can be a PIN diode or HF transistor. The control signal is a binary signal and the code signal is a frequency coded signal. The oscillator circuit can be SAW resonator with RLC oscillation stage (T1, R5, R6, C2, C3, C4, L2). |
