| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission circuit with a simple configuration, at a low cost without production of beat requiring a comparatively small structural space. SOLUTION: The transmission circuit is provided with a local oscillator 6 that generates a local oscillation signal whose frequency is made stable, an ASK modulator 1 that applies ASK modulation to the local oscillation signal to generate an ASK signal, a multiplier 8 that multiplies a frequency of the local oscillation signal to generate a frequency multiplied signal, a mixer 3 that mixes the frequency of the ASK signal with the frequency of the multiplied signal to generate a mixed signal, a band-pass filter 4 that receives the mixed signal and provides an output of an up-convert signal selectively whose frequency is the sum of the frequency of the ASK signal and the frequency of the multiplied signal, and an output amplifier 5 that amplifies the up-convert signal to generate a transmission signal. In this case, since the mixer 3 mixes the frequency of the ASK signal with the frequency of the multiplied signal, it is not required to provide separately a local oscillator generating a mixed signal, and then the transmission circuit with a simple configuration, at a low cost where no beat is produced is realized. |
