Bluetooth radio

Bluetooth 2 way radios, is a function of the radio with blue tooth, blue tooth adapter through interphone, use blue tooth headset to listen to radio receive speech information.
Working principle
1, launch part:
Phase ring and voltage control oscillation (VCO) produce launch rf carrier signal, after buffer amplifier, driver amplification, amplifiers, produce rated rf power, after antenna low-pass filter, suppress harmonic composition, and then through the antenna launch out.
2, receiving part:
Receiving part to second frequency conversion specialized superheterodyne way, from the input signal after sending and receiving antenna transform circuit and band pass filter rf after amplification, after band pass filter and into a frequency mixing, will come from rf signal from the amplification , phase lock loop of the circuit frequency synthesizer vibration signal of the first, in the first mixers place frequency mixing and produce the first intermediate frequency signal. The first intermediate frequency signal through the crystal filter to further eliminate clutter signal of adjacent to the word. After the first intermediate frequency signal of the filter into the intermediate frequency processing chip, and the second this vibration signal frequency mixing generation again the second intermediate frequency signal, the second intermediate frequency signal through a ceramic filters filter out useless stray signals, be amplified and popularly used, produce the audio signal. Audio signal through the amplification, band pass filter, to increase of circuit, into the volume control circuit and power amplifier amplification, drive the speaker, to get people to the required information.
3, a signal and modulation circuit:
The voice through the microphone converts audio electrical signal, audio signal through the amplifier circuit, the aggravating circuit and band pass filter into the vco directly modulation.