JPH0576089A - Receiver - Google Patents

Abstract

PURPOSE:To develop the receiver capable of outputting a pulse signal with the constant pulse width at all times regardless of the level of an optical signal. CONSTITUTION:The receiver consists of a light receiving element 19 converting an optical signal to an electric signal, a capacitor 12 differentiating the output signal of the light receiving element 10, diodes 16 and 17 rectifying the output signal of the capacitor 12 with it divided into two systems, a capacitor 18 differentiating the output of the diode 16, a capacitor 19 differentiating the output signal of the diode 17 by the integrated constant different from that of the capacitor 18, and a comparator 22 comparing the integrated voltage signals of the capacitors 18 and 19 and generating a pulse signal according to the compared result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver, and more particularly to a remote control device for converting a burst signal by light into an electric signal and using the converted electric signal as a control signal. The present invention relates to a suitable receiving device.

[0002]

2. Description of the Related Art A communication system using a burst signal is adopted when the amount of information transmitted is small when performing communication using an optical signal, for example, when the power source of an electric device is turned on and off. Has been done.

A device shown in FIG. 3 is known as a device for receiving the burst signal. This device includes a light receiving element 50, a load resistor 51, a differential component detecting capacitor 52, an amplifier 53, a filter capacitor 54, and an AG.
It comprises a C amplifier 55, a capacitor 56, a diode 57, a resistor 58, a diode 59, a resistor 60, an integrating capacitor 61, and a discharging resistor 62. In this device, when the burst signal 63 is input to the light receiving element 50, the light receiving element 50 causes the burst signal 63 to be input.
Is converted into an electric signal, and the differential component of the converted electric signal is detected by the capacitor 52.

The output signal of the capacitor 52 is amplified by the amplifier 53 and then detected by the diode 59 through the filter capacitor 54. The detected electric signal is the resistance 60,
It is designed to be integrated by the capacitor 61.

When a detection signal is output from this device, an AGC voltage proportional to the detection signal is output from the amplifier 55 to the amplifier 53, and the output voltage of the amplifier 53 is AG.
It will be adjusted according to the C voltage. However, in this device, the AGC circuit does not operate at the initial point of time when the burst signal 63 is received, and since the burst signal 63 is generated in a short time, the gain of the amplifier 55 is not adjusted, There are problems that the level of the detection output does not become constant depending on the level of the burst signal 63 or that a noise signal is received.

As a conventional device of this type, there is known a device which does not include an AGC circuit as shown in FIG.
This device includes a light receiving element 64, a load resistor 65, a differential component detecting capacitor 66, an amplifier 67, a capacitor 68, diodes 69 and 70, a resistor 71, and an integrating capacitor 7.
2, a discharge resistor 73, and a comparator 74.

In this apparatus, the differential component of the electric signal generated from the light receiving element 64 is extracted by the capacitor 66, the extracted electric signal is amplified by the amplifier 67, rectified by the diode 70, and the rectified signal is resistance-converted. 71 and the condenser 72, and the integrated signal is compared with the reference value by the comparator 74. According to this device, when the level of the pulse signal obtained by detecting the burst signal 63 exceeds the reference voltage, an on / off signal corresponding to the burst signal 63 can be output.

[0008]

However, in the conventional apparatus, as shown in FIG. 5, when the level of the burst signal 63 changes due to the distance of the transmission source or the like, the level of the burst signal 63 is changed according to the level of the burst signal 63. Change the output signal level. That is, when the level of the burst signal 63 is low, the signal indicated by the characteristic A is input to the comparator 74, and conversely, when the level of the burst signal 63 is high, the signal indicated by the characteristic B is compared. Input to the computer. Therefore, pulse signals having different pulse widths are output according to the level of the burst signal 63.

It is an object of the present invention to develop a receiver capable of always outputting a pulse signal having a constant pulse width regardless of the level of the optical signal.

[0010]

In order to achieve the above-mentioned object, in the present invention, photoelectric conversion means for converting an optical signal into an electric signal, and differentiating means for differentiating an electric signal output from the photoelectric conversion means, A pair of rectifying means for rectifying the output signal of the differentiating means into two systems, a first integrating means for integrating the output signal of one rectifying means, and an output signal of the other rectifying means are different from the first integrating means. A second integrating means for integrating with an integration constant; and a comparing means for comparing the output signal of the first integrating means with the output signal of the second integrating means and outputting a signal according to the comparison result. We propose a receiver that does.

[0011]

According to the above-mentioned receiving device, after converting an optical signal into an electric signal, the electric signal is differentiated, the differentiated electric signal is divided into two systems and rectified, and each rectified signal is integrated with different integration constants. Then, since the integrated signals are compared with each other and the pulse signal according to the comparison result is output,
Even if the level of the optical signal changes, each integrated value changes proportionally according to the level, and it is possible to always output a signal having a constant pulse width regardless of the level of the optical signal.

[0012]

An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the receiver of this embodiment includes a light receiving element 10, a load resistor 11, a differential component detecting capacitor 12, an amplifier 13, a filter capacitor 14, a diode 15, rectifying diodes 16 and 17, The integrating capacitors 18, 19, discharging resistors 20, 21, a comparator 22, a voltage follower 23, and a variable resistor 24 are provided.

The light receiving element 10 is sensitive to the burst signal generated by light and converts the burst signal into an electric signal. Then, the output signal of the light receiving element 10 is differentiated by the capacitor 12, and the differential component is amplified by the amplifier 13.

The output signal of the amplifier 13 is output through the filter capacitor 14 and is input to the rectifying diodes 16 and 17 of the two systems. The electric signal input to the diode 16 is rectified by the diode 16 and then integrated by the integrating means including the capacitor 18, and the integrated signal is input to the inverting terminal of the comparator 22.

On the other hand, the electric signal input to the diode 17 is rectified by the diode 17 and then integrated by the integrating means composed of the capacitor 19, and the integrated signal is obtained by the voltage follower 23 and the variable resistor. It is input to the non-inverting terminal of the comparator 22 via 24.

The time constant of the charging / discharging circuit consisting of the capacitor 19 and the resistor 21 is set larger than that of the charging / discharging circuit consisting of the capacitor 18 and the resistor 20. The electric signal integrated by the capacitor 19 is divided by the variable resistor 24 via the voltage follower 23, and the comparator 2 outputs a signal having a lower level than the integrated voltage signal of the capacitor 18.
Entered in 2. That is, as shown in FIG. 2A, a signal having a characteristic 100 is input to the inverting terminal of the comparator 22, and a signal having a large time constant such as the characteristic 101 is input to the non-inverting terminal. It will be entered.
Then, the levels of the signals as shown by characteristics 100 and 101 are compared by the comparator 22, and the pulse as shown in FIG. 2B is output from the comparator 22 as the reception output signal. In this case, even if the level of the burst signal changes, the electric signals branched into two systems are integrated at a constant ratio, so that both the signal 100 and the signal 101 change according to the level of the burst signal, Bar from the comparator 22
A pulse signal having a constant pulse width is output regardless of the level of the strike signal. Therefore, the verification of the pulse width can be performed with high accuracy.

Furthermore, if this received output signal is used as an ON / OFF control signal for various electric devices, it is possible to accurately control the various electric devices regardless of the level of the burst signal. Further, unlike the conventional example, since the AGC circuit is not provided, a required signal is output at the same time when the reception is started. Furthermore, in the conventional receiver that compares the integrated voltage signal with the reference voltage, the reference voltage is often set to a low value so as to reliably receive the weak burst signal, but this causes pulse conversion of noise. May be output. In this respect, in the above embodiment, noise is input to both input terminals of the comparator, so that such a problem of the conventional example is solved.

[0018]

As described above, the receiving apparatus according to the present invention differentiates an electric signal obtained from an optical signal, divides the differentiated signal into two systems, and integrates the electric signals of each system with different time constants. Since the integrated values are compared to generate the pulse signal, it is possible to always generate a pulse signal having a constant pulse width regardless of the level of the optical signal.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a receiving apparatus showing an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the receiving device shown in FIG.

FIG. 3 is a configuration diagram of a receiving device shown as a conventional example.

FIG. 4 is a block diagram of a receiving device shown as another conventional example.

FIG. 5 is a waveform diagram for explaining the operation of the receiving device shown as the conventional example.

[Explanation of symbols]

 10 light receiving element 12 differential component detecting capacitor 13 amplifier 16 and 17 rectifying diode 18 and 19 integrating capacitor 20 and 21 discharge resistor 22 comparator 23 voltage follower

Claims (1)

[Claims] 1. A photoelectric conversion means for converting an optical signal into an electric signal, a differentiation means for differentiating an electric signal output from the photoelectric conversion means, and a pair of rectifiers for rectifying an output signal of the differentiation means in two systems. Means, first integrating means for integrating the output signal of one rectifying means, second integrating means for integrating the output signal of the other rectifying means with an integration constant different from that of the first integrating means, and first integrating means. A receiving device comprising: a comparing unit that compares an output signal with an output signal of the second integrating unit and outputs a signal according to a comparison result.