JPH07120996B2 - Data sending / receiving device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission / reception device, and is particularly suitable for a communication device such as an intercom.

2. Description of the Related Art Conventionally, when configuring a device that receives and detects a control signal from a speech path in which a voice signal and a control signal are superimposed and transmitted, and sends a control signal to the speech path, Equipped with an oscillator for transmitting signals with distant frequencies, a bandpass filter that passes only the frequency band of the control signal from the signal received from the communication path, and a waveform shaping circuit that can demodulate the control signal by receiving the signal ing.

Hereinafter, a conventional data transmission / reception device as described above will be described with reference to the drawings.

FIG. 2 is a block diagram of a conventional intercom data transmission / reception circuit. In FIG. 2, reference numeral 10 denotes an interface transformer for transmitting / receiving data between the device and the communication path, and 1 denotes signals other than frequency components of data from a signal received from the communication path via the interface transformer 10. It is a bandpass filter for removing unnecessary components. 2 is an amplifier for amplifying the signal output from the filter 1 to a predetermined level, 3 is envelope detecting means for extracting the envelope of the output signal from the amplifier 2, and 4 is an output signal from the envelope detecting means 3. Is converted into a digital signal which can be read by the control means 5, 5 is a control means for sending the transmission data to the communication path and analyzing the received data, and 6 is an output from the oscillator 12 from the control means 5. A switching transistor which is intermittent according to a control signal, 7 is a transistor for sending transmission data to a communication path, 8 and 9 are resistors, 11
Is a communication path and 12 is an oscillator.

The operation of the data transmission / reception device configured as described above will be described below.

First, the operation when sending data to the communication path 11 will be described. The oscillator 12 is oscillating at a predetermined frequency. When no data is sent to the communication path 11, the output terminal PO of the control means 5 is at the logic level "1". Therefore, the base current flows through the switching transistor 6, the collector-emitter is turned on, and the output from the oscillator 12 is connected to the ground and is not sent to the communication path 11. When the output terminal PO of the control means 15 becomes the logic level "0", the base current does not flow in the switching transistor 6, the collector-emitter is turned off, and the output from the oscillator 12 is not connected to the ground. Therefore, the signal from the oscillator 12 is applied and amplified to the base of the transistor 7, and the interface transformer 10 and the resistors 8 and 9 serve as loads to generate an output signal at the collector. This output signal is sent to the communication path 11 via the interface transformer 10.
By changing the level of the output terminal PO of the control means 5 in accordance with the logic levels "1" and "0" of the data, the tone burst format data is sent to the communication path 11.

Next, the operation of receiving data coming from the communication path 11 will be described. The data coming from the communication path 11 is taken out from the connection point of the resistors 8 and 9 through the interface transformer 10. Since this signal contains not only data but also voice signals and noise, the filter 1 removes frequency components unnecessary for data detection. The filter 1 is a bandpass filter that passes only frequencies in the vicinity of frequencies forming data. The reception signal from which unnecessary frequency components have been removed by the filter 1 is amplified to a predetermined level by the amplifier 2 and is input to the envelope detecting means 3 to remove the high frequency components constituting the data and the envelope thereof. To be extracted. This signal is input to the waveform shaping circuit 4, converted into a digital signal that can be read by the control means 5, and the output signal is input to the input terminal PI of the control means 5. In this way, when the tone burst format data is received from the communication path 19,
An output corresponding to the content of the data (that is, logic level "1", "0") is obtained, and the data is demodulated. Control means
14 analyzes this data signal and controls the intercom, for example.

Problems to be Solved by the Invention However. In the above-mentioned configuration, the band pass filter needs to have a narrow band in order to prevent malfunction of the device. Therefore, it is necessary to use high precision components as components, which is expensive. It was. Further, it is easily affected by the surrounding environment such as temperature and humidity, which is disadvantageous in terms of reliability.

Furthermore, it is necessary to adjust both the frequency of the signal that constitutes the data to be transmitted and the center frequency of the filter that receives and detects the data, which has led to an increase in the number of manufacturing steps.

Means for Solving the Problems In order to solve this problem, the data transmission / reception device of the present invention has an oscillating means for generating a signal of a preset frequency and an output of the oscillating means intermittently connected to a communication path. It is composed of data modulating means for transmitting data and data demodulating means for generating an output signal when the frequency of the signal input from the communication path and the frequency of the oscillating means match.

With this configuration, the data signal received from the communication path is compared with the frequency of the oscillating means by the data demodulating means, and when the two frequencies match, the output is output to demodulate the received data.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a data transmission / reception device according to an embodiment of the present invention. In FIG. 1, the same components as in the conventional example of FIG. 2 are designated by the same reference numerals. Reference numeral 12 is a filter for removing unnecessary components other than the frequency component of the data from the signal received from the communication path via the interface transformer 10. In this embodiment, a high pass filter is used. 2 is an amplifier for amplifying the signal output from the filter 12 to a predetermined level, 13 is a frequency for comparing the frequencies of the signals from the oscillator 14 and the amplifier 2 and the signal from the oscillator 14, and generating the output signal when they match. A phase detector having a comparison means 15. Reference numeral 4 is a control means for transmitting the transmission data to the communication path and analyzing the received data, 6 is a switching transistor for intermittently outputting the output from the oscillator 14 according to the control signal from the control means 4, and 7 is transmitting the transmission data to the communication path. Transistors for this purpose, 8 and 9 are resistors, 11 is a speech path, and 10 is an interface transformer that sends and receives data between this device and the speech path.

The operation of the data transmission / reception device configured as described above will be described below.

First, the operation when sending data to the communication path 11 will be described. The oscillator 14 oscillates at a predetermined frequency. When data is not transmitted to the communication path 11, the output terminal PO of the control means 4 is at the logic level "1". Therefore, the base current flows through the switching transistor 6, the collector-emitter is turned on, and the output from the oscillator 14 is connected to the ground and is not sent to the communication path 11. When the output terminal PO of the control means 4 becomes the logic level "0", the base current does not flow in the switching transistor 6, the collector-emitter is turned off, and the output from the oscillator 14 is not connected to the ground. Therefore, the signal from the oscillator 14 is applied and amplified to the base of the transistor 7, and the interface transformer 10 and the resistors 8 and 9 serve as loads to generate an output signal at the collector. This output signal is sent to the communication path 11 via the interface transformer 10.
By changing the level of the output terminal PO of the control means 4 in accordance with the logic level "1" or "0" of the data, the tone bust format data is sent to the communication path 11.

Next, the reception of data coming from the communication path 11 will be described. The data coming from the communication path 11 is taken out from the connection point of the resistors 8 and 9 through the interface transformer 10. Since this signal includes a voice signal, noise, and the like in addition to data, the filter 12 removes frequency components unnecessary for data detection. The filter 12 may be a simple high pass filter. The reception signal from which unnecessary frequency components have been removed is amplified to a predetermined level by the amplifier 2 and input to the frequency comparison means 15 of the phase detector 13. This signal is compared with the frequency of the oscillator 14, and if the frequencies match, the output signal is input to the input terminal PI of the control means 4. In this way, when the tone burst format data is received from the communication path 9,
Since the phase detector 13 outputs a detection signal according to the presence or absence of a predetermined frequency component, an output corresponding to the content of the data (that is, logic level "1", "0") is obtained and the data is demodulated. . The control means 4 analyzes this data signal and controls the intercom.

Note that the phase detector can specify an integrated circuit for a tone decoder, which is available at a very low price at the present time, and the number of external parts is extremely small, so that a highly reliable data transmission / reception device can be provided at a low cost. Can be configured at cost.

As described above, according to the present invention, the oscillating means for generating the signal of the preset frequency, the data modulating means for intermittently outputting the output of the oscillating means and sending the data to the speech channel, are inputted from the speech channel. The data demodulating means that generates an output signal when the frequency of the signal and the oscillating means match allows data signals to be sent and received with a small number of parts, and there is only one adjustment point, which is highly reliable and low cost. It is possible to obtain the data transmission / reception device of.

[Brief description of drawings]

FIG. 1 is a block diagram of essential parts in an embodiment of a data transmitting / receiving device of the present invention, and FIG. 2 is a block diagram of essential parts of a conventional data transmitting / receiving device. 1 ... Filter 2 ... Amplifier 3 ... Phase detector 4 ... Control means 5 ... Switching transistor 6 ... Transistor 7,8 ... Resistor 9 ... Communication path 10 ... Interface transformer 13 ... Oscillator 14 ... … Frequency comparison means

Claims (1)

[Claims] 1. An oscillating means for generating a signal of a preset frequency, a data modulating means for sending data to a speech path in which the output of the oscillating means is intermittent, a signal inputted from the speech path and the oscillating means. And a data demodulation means for generating an output signal when the frequencies of the data are matched.