JPS60204130A - Transmitter-receiver using amplitude modulation system - Google Patents

Abstract

PURPOSE:To attain talking witn high quality and reception/transmission of a signal through simple constitution by adopting a system where a subcarrier is used and it is amplitude-modulated by a signal wave to obtain a deep modulation independently of the frequency of a carrier. CONSTITUTION:A sawtooth wave whose frequency is varied is generated from a sawtooth wave generating circuit 1 of a width modulation means of a transmission side device, the saw tooth wave from the circuit 1 is fed to an amplitude modulation circuit 3 and the wave is modulated by a voice signal from a microphone 2. The output from the modulation circuit 3 is shaped into a square wave applied with amplitude modulation by a shaping circuit 4 and the square wave is inputted to an FF circuit 5. Output Q, Q' of the circuit 5 control alternately analog switches 6-1, 6-2 and main carriers F1, F2 are generated from a main carrier generator 7. Then a deep modulation is obtained independently of the frequency of the carrier, and talking and data with high quality are transmitted and received among the noise eliminating means, a resonator and the receiver having the 1st and 2nd detecting circuits with simple constitution.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a transmitting/receiving device using a width modulation method, and is particularly applicable to telephones and ink horns that use relatively low frequency carrier waves (for example, using an AC line). , simple m1
There is a PA system suitable for transmitting/receiving devices (such as computers, various digital h-type control devices, etc.).

[Background technology]

The present invention 1, 1 As described in the above technical field, this invention has a wide range of application fields, and will be explained below using a telephone as an example.

So-called parent-child telephones have become popular, allowing one telephone (external line) to be used with multiple telephones and making and receiving calls from any telephone. Many features have been added, such as being able to talk to each other (extension lines), being able to hold and transfer incoming calls from outside lines, and preventing other phones from listening to incoming and outgoing calls. Things are also put into practical use.

Conventionally, telephones using this AC fin have adopted an FM modulation method, but in order to prevent interference with radios, televisions, etc., a relatively low frequency (for example, 150 to 45
0k 1-1z > carrier waves have been used. As a result, it is not possible to obtain a deep modulation depth (q), causing problems such as distorted audio and poor S/N due to low detection output.Furthermore, when the carrier frequency drifts, the detection output becomes large. It has an influence.Furthermore, FM
In the case of the modulation method, the detection circuit on the receiving side is quite complex.

Above) In addition to the above, FM modulation systems with low carrier frequencies have various problems, and the adoption of alternative modulation systems is being considered not only for telephones but also for various application fields.

(Purpose) The purpose of the present invention is to solve the above-mentioned conventional problems, to be applicable not only to telephones but also to intercoms, simple radios, various digital system early start devices, etc., and to achieve high quality with a relatively simple circuit configuration. The purpose of the present invention is to provide a transmitting/receiving 'a@' which can realize good communication and signal exchange.

〔composition〕

In order to achieve the above object, the present invention employs a width modulation method in which a subcarrier is used and the width of the subcarrier is modulated by a signal wave (for example, voice). That is, the transmitting/receiving device of the present invention has the following configuration.

The transmitting side device includes means for changing the width of the transmitted wave 81, means for shaping the variable output from the width modulating means into a square wave, and a flip-flop circuit inputting the square wave generated by the shaping means. A first analog switch operated by the output Q of the Frimbuff L1 tube circuit, a second analog switch operated by the output Q, and two main switches having different frequencies depending on the operation of the first and second analog switches. and a transmission output generating means for alternately generating carrier waves F + + F 2 , and the receiving side device receives the transmission output from the transmitting side device and removes noise components superimposed on the received signal. and,
a resonant circuit that resonates with the main carrier F1 of the received signal obtained through the noise removal means; a first detection circuit that detects an envelope waveform obtained through the resonant circuit; and demodulation means including a second detection circuit for detecting the width modulated square wave obtained by the shaping means and demodulating the signal wave.

[Actual example]

Embodiments of the present invention will be described below with reference to the drawings.

In order to simplify the explanation, it is assumed that the present invention is applied to a telephone, and the signal wave to be modulated is an audio signal.

First, the transmitting side device will be explained.

FIG. 1(a) is a block diagram of a transmitting device according to the present invention;
FIG. 5B is an explanatory diagram of waveforms of each part.

The width modulation means is a sawtooth wave Fp (
For example, a sawtooth wave generation circuit 1 that generates 8 to 20kHz>, and a sawtooth wave generation circuit 1 that generates a sawtooth wave F
The width modulation circuit 3 modulates the signal waveform p with an audio signal (signal wave) generated by the microphone 2. The modulated output from the width modulation circuit 3 is shaped by the shaping circuit 4 into a square wave with a sharp width modulation (see ◯ in FIG. 1(b)).

The square wave is input to the flip-flop circuit 5, and its outputs Q and Q are applied to the analog switches 6-+ and 6-2, respectively, and the main carrier oscillator 7 is output according to the on/off of the analog switches 6-1 and 6-2. is a main carrier wave F1. having a constant amplitude. F
2 are generated alternately. The main carrier wave F1. The power of F2 is amplified by the power amplifier 8, and the transmission output is sent to the output terminal 9 [Fig.
).

Note that the width modulation is applied to the main carrier wave F1, and the relationship with the main carrier wave F2 is F+-F2+ΔF, where ΔF is 10 to 30 kHz.

Next, the receiving side device will be explained.

FIG. 2(a) is a block diagram of the receiving side apparatus according to the present invention, and FIG. 2(b) is a diagram illustrating waveforms of each part.

The above transmission output is input to the input terminal 10. This input (
Since the signal g (received signal) contains a noise component during transmission, it is passed through a noise removal means to remove it.

The noise removing means is a bandpass filter 11. High frequency amplifier 12. It includes a limiter circuit 13.

The received signal whose AM noise has been clipped by the limiter circuit 13 is passed through a resonant circuit 14 that resonates at the frequency of the main carrier wave F1. The envelope signal ([E sln ωpt] sin w 1t ) obtained through the resonant circuit 14.

However, the waveform of ωp = 2πFp, ω1 = 2πF) is as shown in ■ in Fig. 2 (11), and it is passed through the first detection circuit 15 and then as shown in Detection output (E
sinωat) is obtained. This detection output is passed through a subcarrier amplification/shaping circuit 16 that amplifies and shapes it into a square wave as shown in Figure 2 (
Extract the width-modulated square wave shown in (■) in b). This width modulated square wave is input to demodulation means. The demodulation means includes a second detection circuit 17 for extracting the audio signal (signal wave) and a low-pass filter 18 for removing residual components of the carrier wave, and the detection circuit output eo shown in (■) in FIG. 2(b) is −
−8·ΔE sin cc+”pt, where: detection constant is obtained.The output of the low-pass filter 18 is amplified by the audio amplification circuit 19 and the audio signal (signal wave) is output to the output terminal 2.
Output to 0.

The above-mentioned transmitting and receiving device performs transmission and reception using a width modulation method. Note that Figures 1 and 2 only show the basic components of the device;
The same applies to TI equipment), which requires various control functions (for example, holding and transferring incoming calls from outside lines, etc.), and it is necessary to add a control unit for this purpose.

FIG. 3 is a block diagram showing an example in which a control section is added to the receiving side device according to the present invention. The configuration of the portion preceding the first detection circuit 15, which is common to FIG. 2(a), is omitted from illustration.

The control unit 21 includes a plurality of tone detection circuits (for example, 1Ok H
z, 12kHz, 14kHz ・－・・－
・rD item) 22 (22-+ + 22-2122-
3. ...) and analog switches 23 (23-+, 23-2, 23-3) connected to each of them.
,...). The tone detection circuit 22 performs tone detection on the square wave output of the subcarrier amplification/shaping circuit 16, detects the period of the subcarrier on the transmitting side, and thereby performs various controls via the ablog switch 23. FIG. 3 shows, as an example, the case where the output through the low-pass filter 18 is turned on and off.

By adding the control section in this way, the glJ carrier wave can be used as a control signal, and the frequency change range is wide (for example, 8 to 20 kHz), so about 10 types of control signals can be used. Note that the audio signal (signal wave) does not affect the control signal.

〔effect〕

As explained above, the present invention uses a width modulation method in which the number of signals (audio signals) is superimposed on a subcarrier, so there are various advantages as described below.

■ A deep modulation depth can be obtained regardless of the carrier frequency, and high-quality calls (signal exchange) can be made even at low frequencies.

■ Even if there is a slight drift change in the carrier frequency, the detection output will not be affected.

■ Since a limiter is applied to both the main carrier and subcarrier on the receiving side, noise components are removed and almost no AM noise is generated.

■ Since the control signal and the audio signal (signal wave) can be superimposed, the control functions can be operated during a telephone call.

■ Since the subcarrier is a square wave and the period can be changed in many ways, it can be handled as a digital signal and can be easily interfaced with other digital circuits and computers.

■ Compared to conventional FM modulation methods, it is less susceptible to frequency fluctuations caused by cross-modulation and external noise.

■ Compared to the conventional FM modulation method, the circuit configuration on the receiving side is relatively simple, and a large detection output can be obtained.

■ Since the control signal and the voice signal can be superimposed, the control signal is always output during a call, so by making this control signal a unique signal, there is no need to worry about the call being intercepted by other devices.

[Brief explanation of drawings]

FIG. 1 <a> is a block diagram of the transmitting side device according to the present invention, FIG. 3 is an explanatory diagram of waveforms of each part, and FIG. 3 is a block diagram showing a control part of the receiving side apparatus of the present invention. 1... Sawtooth wave generation circuit, 2... Microphone, 3... Width modulation circuit, 4... Shaping circuit, 5... Nori Tube flop circuit, 6 (6-+
, 6-2 >...Analog switch, 7...
...Main carrier oscillator, 11...Band pass filter, 13...
・Limiter circuit, 14... Resonant circuit, 15... First detection circuit, 16... Subcarrier amplification/shaping circuit, 17...
. . . second detection circuit, 18 . . . low pass filter, 21 . . . control unit. Applicant Taishi Trading Co., Ltd. Agent Patent Attorney Increase 1) Takeo Figure 2 (0) (b) <'tpyrrre) Figure 3 A Procedural Amendment (Method) % Formula % 1. Case Indication 1988 Patent Application No. 60072 No. 2, Name of the invention Transmitting/receiving device using width modulation method 3, Relationship with the amended case Patent applicant Shouan Address 3-39-11 Nishiogi, Shoan, Suginami-ku, Tokyo h
Itaishikoueki City Nishihagi 2Wi Name: Taishi Trading Co., Ltd. 4, Agent: 3rd floor, Ginza Ooi Building, 101t5, Ginza 2-chome, Chuo-ku, Tokyo 104 Phone: 03 (545) 2/118 (
6. Subject of amendment (1) Document certifying authority of agency (2) Brief description of drawings in the specification )
” I corrected myself.

Claims (1)

[Claims] A transmitting/receiving device using a width modulation method in which a signal wave such as voice is modulated in width m, y by one subcarrier wave, and a waveform in which the modulated wave is placed on the main carrier wave is used for transmission. means for width modulating a signal wave, means for shaping a modulated output from the width modulation means into a square wave, a flip-flop circuit to which the square wave generated by the shaping means is input, and the flip-flop circuit. A first analog switch operated by the output Q, a second analog switch operated by the output Q, and two main carrier waves Fl and F2 having different frequencies alternately depending on the operation of the first and second analog switches. the receiving side device receives the transmission output from the transmitting side device and removes a noise component folded onto the received signal;
a resonant circuit that resonates with the main carrier wave F1 of the received signal obtained through the noise removal means; a first detection circuit that detects the envelope waveform 1q obtained through the resonant circuit; means for shaping the output of the detection circuit into a square wave;
Detecting the width modulated square wave by the ti-type means 1
1. A transmitting/receiving device using a width modulation method, comprising: demodulating means including a second detection circuit that demodulates a Δ signal.