Infrared receiver and method for improving frequency response of input end of infrared receiver

Abstract

The invention relates to an infrared receiver and a method for improving the frequency response of the input end of the infrared receiver. The infrared receiver comprises an input unit, a preamplifier, a variable gain amplifier, an amplitude limiter, a second band pass filter, a demodulator and an output unit which are sequentially connected, wherein a photosensitive diode (LED light-emitting diode-r) is embedded in the input unit; the infrared receiver also comprises an automatic gain controller and a corresponding frequency adjusting control unit, wherein the automatic gain controller is connected between the variable gain amplifier and the output end of the demodulator, and the corresponding frequency adjusting control unit is connected with the control end of the second band pass filter; and a first band pass filter containing an internal equivalent junction capacitor of the photosensitive diode (CPD) is also embedded in the input unit, and the control end of the first band pass filter is electrically connected with the corresponding frequency adjusting control unit. The method comprises a step of adjusting the center frequency of the first band pass filter to the carrier frequency of an infrared remote control signal. According to the infrared receiver and method thereof disclosed by the invention, the frequency response of the input end is improved, and the bearing range to direct-current photocurrent noises is expanded while the selectivity of input signals is increased.

Description

technical field [0001] The invention relates to electronic circuit technology, in particular to an infrared receiver and a method for improving the frequency response of its input terminal. Background technique [0002] At present, the infrared frequency band does not need to be approved by the relevant national departments, and the compatibility is good. The infrared receiving circuit is widely used in various fields, such as home appliances, toys, etc. In addition to the infrared remote control signal, the signal received by the infrared receiver usually includes various noises. These noise signals mainly come from various ambient lights, including sunlight, incandescent lamps, and fluorescent lamps. The noise generated by sunlight and incandescent lamps is white noise, that is, DC photocurrent noise; the noise generated by fluorescent lamps, with a frequency between 100 Hz and tens of KHz, is AC photocurrent noise. [0003] Traditional infrared receiver, the circuit fram...

AI Technical Summary

Problems solved by technology

[0027] Since the CPD varies greatly in various circuit applications, if the central angular frequency ω2 of the band-pass filter is not adjusted, ω2 is likely to deviate far from the carrier frequency of the infrared remote control signal, causing noise from other frequency bands to enter the infrared receiver, or make the receiving sensitivity of the infrared receiver worse or even completely unable to receive the infrared remote control signal

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