| 摘要 |
<p>A receiver and an audio transmitter which are used for radio-transmission of frequency-modulated audio signals, etc. Signals of 900 MHz band received through a reception antenna (501) are amplified by an RF amplifier (502), supplied to a mixer (504) through a band-pass filter (503), and converted into intermediate-frequency signals having a carrier frequency of 10.7 MHz. The frequency of the intermediate-frequency signals is lower than 1/30 of that of the transmitted signals, and the frequency of the local oscillation is above the transmission frequency. The frequency band of the transmitted signals is so determined that the rate of occurrence of image disturbance is low. Since a single conversion system using the mixer (504) is adopted, the receiver and audio transmitter is simple and inexpensive.</p> |
