Design of wireless transmitting and receiving circuit based on Bluetooth

Circuit principle: Using an LC oscillator, the frequency drift is more serious. The emergence of surface acoustic devices has solved this problem. Its frequency stability is roughly the same as that of crystal oscillators, and its fundamental frequency can reach hundreds of megahertz or even gigahertz. There is no need for frequency multiplication, and the circuit is extremely simple compared to a crystal oscillator. The following circuit is a common transmitter circuit. Due to the use of acoustic surface devices, the circuit works very stably. Even if you hold the antenna, acoustic surface or other parts of the circuit, the transmitting frequency will not drift. It can reach more than 200 meters. At the same time, the receiver can use super regenerative circuit or super heterodyne circuit. The super regenerative circuit has low cost and low power consumption of about 100uA. It has well-adjusted super regenerative circuit sensitivity and one-level high amplification and one-level oscillation. , one-stage mixing and two-stage mid-amp superheterodyne receivers are almost the same. However, the super-regenerative circuit has poor operating stability and poor selectivity, thus reducing its anti-interference ability.