This simple FM receiver is built based on IC TDA7000 with minimum passive component. It can receive entire 88 – 108MHz FM band with good sensitivity. A nice feature of this TDA7000 FM receiver is a voltage controlled oscillator. Instead of using trimmer (variable capacitor), you can tune the frequency by varying the input voltage to the oscillator through 100K potentiometer. The benefits of using potentiometer than trimmer are no more shift frequency when you touch it and easy placement anywhere without need to worry about stray capacitance.
FM Receiver Schematic
- Supply Voltage: 2 – 10V
- Transmission Frequency: 70 – 120MHz
- Power Consumption: 8mA
- AF Audio Output: 75mV
The TDA7000 is a monolithic integrated circuit for mono FM portable radios, where a minimum on peripheral components is important (small dimensions and low costs).
The IC has an FLL (Frequency-Locked-Loop) system with an intermediate frequency of 70 kHz. The i.f. selectivity is obtained by active RC filters. The only function which needs alignment is the resonant circuit for the oscillator, thus selecting the reception frequency. Spurious reception is avoided by means of a mute circuit, which also eliminates too noisy input signals. Special precautions are taken to meet the radiation requirements. The TDA7000 includes the following functions: R.F. input stage, Mixer, Local oscillator, I.F. amplifier/limiter, Phase demodulator, Mute detector, and Mute switch. Download TDA7000 Datasheet.