JPH0449296B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmitting/receiving device for transmitting and receiving information signals.

Conventional configuration and its problems Conventionally, when transmitting a signal from a transmitting device to a receiving device, a square wave, which is a digital pulse output from a microcomputer (hereinafter referred to as a microcomputer), is directly superimposed on a DC voltage and transmitted. However, square waves contain many harmonic components. Therefore a certain frequency band, e.g. 525k
Hz to 1600kHz is the radio frequency band, so it interferes with radio waves when transmitting signals.
This had the problem of poor reception of radio waves.

OBJECTS OF THE INVENTION In view of the above drawbacks, the present invention provides a transmitting/receiving device that does not interfere with wireless equipment such as radios.

Structure of the Invention In order to achieve the above object, a transmitting/receiving device of the present invention includes an oscillation circuit that generates a clock signal, a microcomputer that operates by inputting an output signal of the oscillation circuit, and an information signal to be transmitted to the microcomputer. an input/output circuit that receives and displays signals from the microcomputer; a modulation circuit that modulates the transmission data output from the microcomputer with the output signal of the oscillation circuit; A sine wave circuit that converts the carrier wave component of a modulated signal into a sine wave, an amplifier circuit that power amplifies the output signal from the sine wave circuit, and a signal amplified by the amplifier circuit that is superimposed on a DC power supply or conversely separated. and a demodulation circuit that demodulates the signal separated by the signal superposition and separation circuit and outputs it to the microcomputer.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1a and 1b show circuit configuration diagrams of a transmitting/receiving device in an embodiment of the present invention.

In the figure a, 1 indicates a transmitting/receiving device, which is connected to a commercial power source 3 via terminals 2a and 2b. Reference numeral 4 denotes a power supply circuit, which converts the commercial power supply 3 into a DC voltage necessary for operating an electronic circuit, or converts a voltage for transmission to a transmitting/receiving device. Terminals 5a and 5b connect transmission lines 6a and 6b,
It is used to supply power and transmit/receive information signals to other transmitting/receiving devices, and is connected to both ends of the power supply circuit 4 via the secondary winding 9 of the transformer 7 inserted in series. A capacitor 10 connected in parallel to both ends of the power supply circuit 4, together with the transformer 7, separates the power supply and the information signal.

That is, the capacitance C of the capacitor 10, the transformer 7
The equivalent inductance seen from the secondary winding side of is L, and the respective impedances are Z _C and Z _L ,
Furthermore _, when the frequency of the power supply is ₁ and the frequency of the information signal is ₂ , if the values of _L and C are determined so that Z C ≫ Z _L at frequency ₁ and Z _L ≫ Z _C at frequency 2, then capacitor 1
The power source and the information signal are separated based on the principle that almost only the power source component appears at both ends of the transformer 7, and almost only the information signal component appears at both ends of the secondary winding 9 of the transformer 7. Reference numeral 11 denotes a signal superimposition circuit composed of the transformer 7 and capacitor 10.

As shown, 12 is an oscillation circuit such as a crystal resonator or a ceramic resonator, which sends a clock signal to the microcomputer 13 and is also input as a carrier signal to the modulation circuit 14 for shared use. The modulation circuit 14 includes an information signal output from the microcomputer 13 and the oscillation circuit 1.
The clock signal output from 2 is inputted, amplitude modulated by the amplitude modulation circuit 14, and the square wave signal that is the modulated signal is inputted to the sine wave circuit 15 to make it a signal close to a sine wave, and the amplifier circuit 16 converts it into a signal close to a sine wave. The signal is amplified and an information signal is generated in the primary winding 8 of the transformer 7.

The information signal generated in the primary winding 8 of the transformer 7 is sent out to the transmission lines 6 a and 6 b via the secondary winding 9 and transmitted to the transmitting/receiving device 19 .

Conversely, a signal transmitted from the transmitting/receiving device 19 via the transmission lines 6a, 6b is generated at both ends of the secondary winding 9 of the transformer 7, and appears at the primary winding 8. This information signal is input to the microcomputer 13 after being subjected to amplitude modulation detection and shaping into a digital pulse in the demodulation circuit 17 . Reference numeral 18 denotes an input/output circuit consisting of LEDs, keys, switches, relays, volume, sensors, etc., and its input/output information is communicated with the transmitting/receiving device 19 via the microcomputer 13.

In FIG. 1b, transmission lines 6a and 6b are connected to terminals 20a and 20b, and transmitted power and information signals are input and output. 21
is a diode bridge, and the terminals 20a and 2 are connected even when the transmitted power is DC or AC.
0b and the transmission lines 6a and 6b are made non-polarized to supply a DC voltage with fixed polarity to the power supply circuit 22. 23 is the primary winding 2 of the transformer
4, consists of a secondary winding 25, and a capacitor 26
A signal superimposition/separation circuit 27 is configured. 28
29 is an oscillation circuit, 29 is a modulation circuit, 30 is a sine wave circuit, 31 is an amplifier circuit, 32 is a demodulation circuit, 33 is a microcomputer, and 34 is an input/output circuit, all of which are the same as explained in FIG. 1a.

FIG. 2 is a frequency characteristic diagram of the transmission signal, and A
B is a frequency characteristic diagram of a transmission signal in an embodiment of the present invention, and B is the same frequency characteristic diagram of a conventional example. As you can see from the A and B characteristics in the diagram, 200kHz to 400kHz
By using the present invention, the difference in signal magnitude at In addition, other high frequency components are also significantly lowered, which is in the radio frequency band.
There is almost no interference with radio reception between 525kHz and 1600kHz.

Although tuning transformers are used in the sine wave circuits 15 and 30 in this embodiment, similar effects can be obtained by using operational amplifiers in other embodiments.

Effects of the Invention As described above, according to the present invention, a sine wave circuit for shaping a square wave signal into a sine wave signal is provided in the transmitting/receiving device, and the sine wave circuit converts the output signal from the microcomputer into a sine wave signal. After modulating the carrier wave, the carrier wave is converted into a sine wave and amplified. Since the signal is transmitted in a waveform close to a sine wave, the signal has no harmonic components and does not interfere with radio equipment such as radios. In addition, since sine wave conversion is performed before amplification, the circuit structure can be realized at low cost and simple with a small number of parts.Moreover, since the sine wave conversion part and the amplification part are separate, it can be constructed with small parts. Furthermore, since harmonic components are removed and the signal is transmitted at one frequency, it has the effect of improving transmission efficiency.

Furthermore, since the output signal of the oscillation circuit is shared as the clock signal of the microcomputer and the carrier wave signal when transmitting the data signal, the configuration is simple and inexpensive.

Furthermore, since the oscillation circuit is constructed using a crystal oscillator or ceramic oscillator, the frequency is extremely stable and can be used when modulating with a data signal and then converting it into a sine wave, or when amplifying the signal and passing it through a signal superimposition/separation circuit to the power source. Even when a signal is superimposed on a sine wave circuit or a signal is separated and input into a demodulation circuit, because the variation in carrier frequency is small, the signal level does not attenuate in a sine wave circuit or a signal superposition/separation circuit, and the signal is of extremely high quality. can be transmitted.

Furthermore, the modulation circuit modulates the amplitude of the data signal, and the sine wave circuit converts the carrier wave into a sine wave before transmitting it, so there are almost no harmonic components, and there is no interference or other negative effects on wireless equipment such as radios.
Furthermore, since the sine wave is converted and amplified, the amplifier circuit can be configured in a narrow band and is very inexpensive and easy to configure. Furthermore, compared to frequency modulation, the filter band is narrower and the noise level can be kept low.

[Brief explanation of the drawing]

FIGS. 1a and 1b are circuit configuration diagrams of a transmitting and receiving apparatus according to an embodiment of the present invention, and FIG. 2 is a frequency characteristic diagram of a transmission signal. 4, 22... Power supply circuit, 11, 27... Signal superimposition and separation circuit, 12, 28... Oscillation circuit, 13, 3
3...Microcomputer, 14,29...Modulation circuit, 15,30...Sine wave circuit, 16,31
...Amplification circuit, 17, 32...Demodulation circuit, 18,
34...Input/output circuit.

Claims (1)

[Claims] 1: an oscillation circuit that generates a stable clock signal using a crystal resonator, ceramic resonator, etc., a microcomputer that inputs the output signal of the oscillation circuit as a clock signal and outputs a data signal to be transmitted, and the oscillation circuit a modulation circuit that amplitude-modulates a clock signal whose carrier frequency is stable by sharing the output signal from the microcomputer with the data signal from the microcomputer; and a modulation circuit that converts the carrier wave signal of the data signal modulated by the modulation circuit into a sine wave signal. a sine wave circuit; an amplifier circuit that amplifies a modulated signal obtained by converting a carrier wave into a sine wave in the sine wave circuit; and a demodulation circuit that demodulates the modulated signal separated through the signal superposition and separation circuit and inputs it to the microcomputer.