| 摘要 |
PURPOSE:To suppress the oscillation of a circuit by increasing a switching frequency several times higher than the maximum frequency of a transmission/reception signal to prevent a transmission output from leaking to a receiving side. CONSTITUTION:The transmission signal is inputted to a gate of a transmission output transistor FET1, a drain circuit is provided with a series circuit comprising a transmission and reception line T and a switching element FET2, and resistors R1, R2 having a resistance value of several ohms are connected across an FET2. Then, a pulse having a frequency twice or over the transmission signal frequency is applied to a gate of the FET2. Thus, the integrated waveform across the switching element FET2 is similar to that of the transmission signal and they are in-phase to each other then they are cancelled with each other and no transmission signal is leaked to the output side by adjusting the potential to an equal value by a proper method and inputting the result to both input terminals of a differential amplifier OP. |
