Waveform shaping circuit

Abstract

The present invention relates to a circuit which can reshape waveform of any base value voltage and peak value voltage into regular square wave. The prior waveform reshaping circuit produces a threshold value for comparing through a complex threshold value calculating circuit; and then reshapes the waveform, thereby having the shortcomings of complex structure and poor reshaping efficiency. The present invention reshapes the waveform through a method of delaying comparison. The reshaping circuit is a capacitance or inductance which backward moves the phase of the input waveform and a positive feedback circuit which consists of a voltage dividing resistor used for adjusting the noise margin, so that the waveform of any base value and peak value is reshaped into regular square wave to beneficial for the digital disposal. Thereby the present invention has a good reshaping efficiency. When in use of the infrared data communication system, the present invention has the advantages of greatly increasing the transmission speed and the transmission distance, well overcoming the various unbeneficial factors such as ambient light, photodiode current leakage and transmission power, and not being influenced by the trialing problem which is produced by the PIN when in high speed infrared communication.

Description

technical field [0001] The invention relates to a waveform shaping circuit, in particular to a circuit capable of shaping arbitrary base voltage and peak voltage waveforms into regular square waves. technical background [0002] In the waveform shaping circuit, the base value of many waveforms, especially the waveform at the infrared receiving end, is generally an unknown voltage level, and affected by ambient light and other factors, the voltage value varies in a large range, which is not conducive to waveform shaping; Due to the above factors, it is not conducive to the shaping of the waveform. [0003] At present, the existing waveform shaping systems at the infrared receiving end can be divided into two categories according to the complexity. One is the basic waveform shaping system, as shown in Figure 7. This type of circuit has a simple structure and is widely used, and is mostly used for infrared remote control. In order to enhance the receiving ability of this type...

AI Technical Summary

Problems solved by technology

The remote control distance of the general infrared remote control system is 3-5 meters, and the remote control effect is quite poor when it exceeds 5 meters. When the remote control battery power is weak and other interference factors are large, the effective distance of the remote control is less than 3 meters, or even Shorter

[0012] There are two problems in this circuit. One is that at different distances, the output current of the infrared photodiode varies greatly due to the different light intensity, generally from hundreds (nA) to tens (mA), which requires the The dynamic range of the infrared data receiving circuit is also large

[0013] The second is that during space transmission, when the input signal is strong, there are problems such as slowing down the falling edge of the photocurrent and elongating the tail.

But the problem with this is that when the communication distance is long and the input signal is low, V1 may be greater than the pulse peak value Vp, so the threshold will always be lower than the input signal, so that the signal cannot be restored by shaping

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