Infrared remote control receiving circuit

Abstract

The invention discloses an infrared remote control receiving circuit, which comprises a variable grain amplifier and a limiting amplifier, a band pass filter, a first comparator, a first demodulator, an output module, a second comparator, a second demodulator, an output time detector and a logic arithmetic unit, wherein the variable grain amplifier and the limiting amplifier are used for amplifying a voltage signal and controlling voltage gain; the band pass filter carries out band pass filtering on the output signal of the limiting amplifier; the first comparator compares the output signal of the band pass filter with a first preset potential; the first demodulator demodulates the output of the first comparator; the output module outputs the output of the first demodulator; the second comparator compares the output signal of the band pass filter with a second preset potential; the second demodulator demodulates the output of the second comparator; the output time detector detects whether the time the output of low-level pulse exceeds a preset time or not; the logic arithmetic unit calculates the outputs of the second demodulator, the output time detector and the first demodulator; and the gain of the variable grain amplifier is controlled by an automatic gain controller. The circuit is free from being limited by a signal duty ratio and signal duration when being used for transmitting data signal, and the gain can be correspondingly regulated according to the variation of environment noise.

Description

technical field [0001] The invention relates to an infrared remote control receiving circuit, in particular to an infrared remote control receiving circuit capable of realizing data transmission. Background technique [0002] The principle of infrared remote control transmitting signal is: the signal to be transmitted is modulated by high-frequency carrier, and then emitted by the infrared light-emitting tube on the remote control. The infrared light-emitting tube emits a series of carrier signals (marked as S1 signal, see figure 2 ) and does not transmit a carrier signal (marked as S0 signal, see figure 2 ) to realize the transmission of signal high and low levels. [0003] Such as figure 1 Shown is the traditional infrared remote control receiving circuit. The photodiode 11 receives the light signal and converts it into a weak electrical signal. After being amplified by multi-stage amplifiers such as I-V amplifier 12, variable gain amplifier 13, and limiting amplifier...

AI Technical Summary

Problems solved by technology

In the initial stage, a normal waveform can also be obtained at the output terminal of the output module; but as Vctrl accumulates and rises, the gain continues to decrease, and after a period of time, the output terminal of the output module does not have the correct signal output

Therefore, traditional technology is not suitable for infrared transmission of data signals

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