JPS6032465A - Transmitter-receiver - Google Patents

Abstract

PURPOSE:To improve the reliability of remote control by deciding an information signal carried in a carrier frequency at a deciding circuit having two threshold values, charging a differentiating circuit when the signal is not contained between the threshold values, discharging the circuit when the signal exists between the values, and decoding and reproducing the information signal with fidelity. CONSTITUTION:An AC input is converted into a DC power supply VB and a stabilized power supply 12V or the like by a power supply circuit 3 of a transmitter-receiver 1. Further, a choke coil 9 of a signal detecting circuit 6 connected to transmission lines 5a, 5b blocks the transmitted information signal and a tuning transformer 10 detects the signal. A demodulation circuit 13 and a modulation circuit 14 are connected to the transformer 10 to provide the transmission and reception function to the transceiver 1. The circuit 13 is provided with a differentiation circuit 25 and a deciding circuit 22 comprising comparators 20, 21 having respectively the 1st and 2nd threshold values VREF1 and VREF2. Then the circuit 22 decides the information signal and when the circuit 25 is charged when no signal exists between both the VREF1 and VREF2, the circuit 25 is discharged when the signal exists, and the information signal is decoded and reproduced with fidelity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmitting/receiving device to be applied to a remote control system for remotely controlling gas water heaters, oil boilers, etc. The present invention relates to a circuit configuration of a receiving device suitable for accurate demodulation and reproduction.

Conventional configuration and its problems Traditionally, when controlling a gas water heater, oil boiler, etc. remotely, a dedicated signal line was extended from the device itself, and switches, indicator lamps, etc. were connected to the end of the signal line. It has the most rudimentary structure and has been commercialized numerous times. but,
This method has the disadvantage that the number of signal lines increases and the wiring work becomes complicated. In particular, when connecting multiple remote controllers and attempting to remotely control them from various locations, this type of signal line extension method cannot be used.

Therefore, a remote control method can be considered in which digital signal transmission technology is used to make the information to be transmitted correspond to a digital pin 1-, and the information signal is transmitted serially. However, in order to incorporate and commercialize such digital signal transmission technology into remote control systems for household energy equipment such as gas water heaters and oil boilers, it is necessary that these equipment handle fuels such as gas and stone surfaces. Because of this, reliability of signal transmission is particularly required.
For this purpose, a receiving device is required that faithfully demodulates and reproduces the information signal transmitted from the transmitting device.

Purpose of the Invention The present invention provides a remote control system for household energy equipment such as gas water heaters, right-hand boilers, etc. that utilizes digital signal transmission technology. The purpose of this invention is to provide a circuit configuration of a receiving device for detecting a transmitted information signal and demodulating and reproducing the original information as faithfully as possible, thereby realizing highly reliable transmission and reception operations.

Structure of the Invention The present invention includes a signal detection circuit for detecting an information signal carried at a predetermined carrier frequency, and a signal level detected by the signal detection circuit, which is determined using two threshold values. The demodulation circuit consists of a level judgment circuit that captures only signals above the level, and an integration circuit that demodulates the information signal output from the level judgment circuit. This structure improves the reliability of signal transmission against noise caused by noise, and faithfully demodulates and reproduces the original broadcast signal.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 indicates the entire configuration of the transmitting/receiving device on the power supply side.
Connected to OV.

3 is a power supply circuit A, which converts AC 100V input into a stabilized DC power supply such as +12V, +5V, etc. necessary for electronic circuit operation, and a power supply vB to be supplied to a power supply receiving 1 μm 1 transmitting/receiving device. be. Note that the transmitting/receiving device on the power receiving side has basically the same configuration as the transmitting/receiving device of power supply mechanism 1] except for the power supply circuit, so a description thereof will be omitted.

The terminals 4a and 4b are used to connect transmission lines 5a and 5b to supply power to other transmitting and receiving devices and to transmit and receive alarm signals.
It is connected to both ends 7a and 7b of B.

In the signal detection circuit 6, a capacitor 8 is connected in parallel with the power supply vB, a choke coil/l/9 is connected in series with the transmission line 5a, and a secondary winding 10b of a tuning transformer 10 is connected to a capacitor 11 between the transmission lines. connected via. With this configuration, the information signals coming through the transmission lines 5a' and 5b are blocked by the choke coil V9, and most of them are in tune! Appears at both ends of the lance secondary winding 10b, and the information signal can be detected via a tuned transformer.

Furthermore, if the frequency component of the power supply VB is made much smaller than the carrier frequency of the information signal, the choke coil 9 can have a low resistance to the power supply VB, so that power can be supplied efficiently. , also, capacitor 1
By setting 1 to an appropriate capacitance value, it is possible to prevent the influence of the power supply vB from appearing on the tuned 1-lance secondary winding 10b.

A capacitor 1 is connected to both ends of the tuned transformer primary winding 10a.
2 are connected, and the value is determined so as to resonate at the carrier frequency of the information signal. Moreover, +12V is connected to the intermediate tap, and the structure is such that it oscillates around -1-12V. In addition, a demodulation circuit 1 is connected to the tuned trunk primary winding 10a.
In addition to 3, a modulation circuit 14 can be connected. Therefore, the signal detection circuit 6 also has the function of a signal sending circuit.

In the demodulation circuit 13 in FIG. 2, 15 and 16 are resistors, and the information signal detected at the resonance frequency of the tuned transformer primary winding 10a and the capacitor 12 is transmitted through these two resistors R1.
, R2, and applied to the negative input terminal of the first comparator 20 and the positive input terminal of the second comparator 21. Note that the potential when there is no signal is R2×12 (v). 17, 18
, 11: DWZ Resistors R3, R4, R5 divide the voltage by -1-12Vk and input it to the positive input terminal of the first comparator. A first threshold value (VREFl); A second threshold value (VREF2) is supplied to the negative input terminal of the second comparator.By setting resistors R3, R4, and R5 to appropriate values, no signal VvREFl, It is possible to freely change the voltage difference between the two threshold voltages and the voltage difference between the two threshold voltages set to VREF2'.

1st. The second comparators 20 and 21 both have open collector outputs, and both output terminals are wired OR connected.

The level determination circuit 22 is composed of the following two elements. A capacitor 23 and a resistor 24 are connected to the pressure of the level judgment circuit 22.
The level judgment circuit 2 is connected to an integrating circuit δ consisting of
Charging and discharging are performed according to the logic of No. 2, and the envelope of the information signal is demodulated and reproduced almost faithfully. 26 is a commercial
This is a waveform shaping inverter made with O8 NAND game 1-.

The signal demodulation operation in the above configuration will be explained with reference to FIG. FIG. 3 (al is the original baseband format information signal output from the opposing transmitter; (b) is the signal modulated at the gear rear frequency is input via the tuning transformer; This shows the states applied to the negative input terminal of the first comparator 20 and the positive input terminal of the second comparator 21.As described above, the first comparator 2o
is the voltage applied to the negative input terminal is the first threshold VR
The second comparator 21 outputs L6W when the voltage applied to the positive input terminal is smaller than the second threshold VREF2. Set the output to HIG otherwise.
In order to output an H output, the outputs of the first and second comparators 20 and 21, which are wired to R, have a form as shown in FIG. 3 (,C).

However, L1 In reality, since the integrating circuit 25 is added after that, the capacitor 23 and the resistor 2 are connected as shown in FIG. 3(d).
The waveform is integrated with an integration time constant τ1 determined by 4. Fig. 3 fe) is the output waveform when the threshold level of the NAND gate 26 of the CMO8 is set to vTH, and this is extremely long compared to the original information signal in Fig. 3 (al) by only tA. This shows that faithful signal reproduction has been performed.It also completely eliminates noise such as vN in FIG. 3(b).

For reference, FIG. 4 shows the demodulation operation when the level determination circuit has one threshold value in comparison with FIG. 3. In such a configuration, as shown in Fig. 4 (cl), the period in which the output of the comparator is LOW is reduced, so the integration time constant τ2 must be increased as shown in Fig. 4 [d], and as a result, In the same figure (as shown in el, H is lowered by tB than the original information signal)
This indicates that the IGH period becomes longer and faithful demodulation cannot be performed.

Reference numeral 27 in FIG. 1 is a clock generation circuit, the output of which is supplied as a clock signal to the transmitting/receiving digital logic circuit 28, as well as to the modulation circuit 14 as a carrier signal, and the output terminal of the transmitting/receiving digital logic circuit 28 (
The information signal in baseband format output from the OUT) is modulated by the NAND gate 1-30 in the NAND mode.

The transmitting/receiving digital logic circuit 28 is predetermined in accordance with communication regulations, and in addition to managing reception of information signals,
, input/output information is received with the input/output circuit 29 consisting of switches, relays, volumes, sensors, etc., and is a cost-effective circuit using microcomputer program logic. can be realized.

Effects of the Invention As is clear from the detailed explanation above, the present invention determines an information signal carried on a carrier frequency using a level determination circuit having two thresholds, and when the signal level is equal to or lower than the two thresholds. Since the configuration is such that the integrating circuit connected later is charged when the signal level is not in between, and discharged when the signal level is between two threshold values, the charging period of the integrating circuit can be lengthened and the discharging period shortened. Can be done.

To this end, the discharge time constant is reduced to enable faithful demodulation and reproduction of the information signal.

Furthermore, it is clear that the method has the ability to eliminate noise generated at a level between two threshold values.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a transmitting/receiving device showing an embodiment of the present invention;
Fig. 2 is a circuit diagram of the same part, Fig. 3 a and b. 4c, d, and e are time diagrams showing the process of signal processing in the same part, and FIG. 4a, b, c, ci, and e are time diagrams showing the process of signal processing in the conventional example. 1... Transmitting/receiving device (power supply side), 6...
... Signal detection circuit, 13 ... Demodulation circuit, 22.
... Level judgment circuit, 25 ... Integration circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4

Claims (1)

[Claims] (1) A signal detection circuit for detecting an information signal carried at a predetermined carrier frequency, and determining the signal level detected by the signal detection circuit using two thresholds;
The demodulation circuit consists of a level judgment circuit whose output logic is inverted depending on whether the signal level is between two thresholds or not, and an integration circuit whose charging/discharging is determined by the output logic of the level judgment circuit. Transmitting/receiving device. 2. The transmitting/receiving device according to claim 1, wherein the two threshold values are set at two or more symmetrical levels with the no-signal level in between.