Ultrasonic receiving circuit-receiving circuit composed of discrete components

Ultrasonic remote control receivers generally consist of receiving sensors, amplification detectors, power amplifiers, memory drivers, execution circuits and controlled loads.
Multi-channel remote control adds demodulation and decoding circuits. The ultrasonic receiver receives the ultrasonic wave, converts it into a weak electrical signal, and then amplifies and
detects it (decoding, decoding, decoding) to form a DC level signal, which is latched by the state latch circuit and drives the actuator to implement the control The operation of the controlled object
. In a single-channel remote control, no encoding and decoding circuit is used
, multi-channel control signals cannot be output, and the anti-interference ability
is also poor. Sound wave signals emitted by other sound sources that are
similar to the frequency used by the device may cause the receiver to Controlled objects
may cause malfunctions. The ultrasonic remote control using coding technology
can realize multi-channel remote control. Receiving circuit composed of
    discrete components : The picture shows an ultrasonic receiving circuit
using transistors . vri, VT2 form a resistor-capacitor coupling two-stage amplification circuit, and the input signal is 3-5mV. Ri is a resistor used to reduce impedance and thereby suppress external noise added to the sensor. The output signal is a 40kHz high frequency voltage signal.