JPS6384215A - Voice/data multiplexer - Google Patents

Abstract

PURPOSE:To send a signal at an optimum signal level even if the sensitivity of a transmitter or the sound coupling is in any state by informing it to a talker if a carrier reception level is less than a reference level so as to allow an opposite talker to vary the sending level. CONSTITUTION:A signal level decision means 100 deciding a carrier reception level of a reception transmission signal, an informing means 200 informing the reduction of a reception level and a transmission level variable means 300 for a transmission signal are provided. The means 100 detects the carrier reception level of the reception signal introduced through an acoustic coupler and compares it with a reference level, and when it is decided that the received level is less than the reference level, it is informed to a talker by the means 200. The talker, according to the information, informs it to the opposite talker by voice communication and the opposite talker operates the means 300 to improve the transmission signal level of the opposite equipment. Thus, the transmission signal with sufficiently high transmission signal level is sent. Thus, the deterioration in transmission such as bad coupling state of the acoustic coupler is prevented.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention relates to a voice/data system that combines a frequency division multiplexed signal of data and voice with a handset of a telephone via an acoustic coupler for transmission and reception. Related to improvements in multiplexing equipment.

(Prior art) In recent years, a method has been developed that simultaneously transmits graphic data and audio signals input by hand using a tablet input device using a telephone line, but this type of method uses frequency modulation of a carrier wave by data. However, the carrier wave and the audio signal are frequency division multiplexed and transmitted as shown in FIG. 3, for example. FIG. 4 shows an example of the configuration of a voice/data multiplexing apparatus for implementing this type of transmission system, where 1 indicates a telephone connected to a telephone line 2, and 3 indicates a handset thereof. This device frequency-modulates a carrier wave using input data DT in a frequency modulation circuit 11, limits the band of this modulated carrier wave in a bandpass filter (BPF) 12, converts audio into an audio signal with a microphone 13, and then converts the sound into an audio signal using a band-elimination filter. (B.E.
F) The modulated carrier wave band 14 is attenuated, these modulated carrier waves and the audio signal are combined in an adder 15, and then electro-acoustic converted by the speaker 16a of the acoustic coupler 16 and input to the transmitter of the handset 3. and transmits it from the telephone 811 to the telephone line 2. On the other hand, a frequency multiplexed signal that has arrived via the telephone line 2 is introduced through the receiver of the handset 3 through acoustic-to-electrical conversion by the microphone 16b of the acoustic coupler 16, and this frequency multiplexed signal is transmitted to the BPF 17 and the BE.
After each signal is guided to F19 and the modulated carrier band is separated and extracted by BPF 17, it is demodulated by frequency 111 circuit 18 to reproduce the data and output to a monitor device or the like. Also, the above BEF1
At step 9, the audio signal component is separated and extracted from the frequency multiplexed signal, and this audio signal is sent out as audio from the monitor speaker 20. By using such a device, you can use your existing telephone as is, and it is relatively easy to transmit voice and data at the same time. For example, it is possible to transmit character code information while talking, which is very useful. It's convenient.

However, the acoustic coupling state of the acoustic coupler 16 to the handset 3 tends to change depending on the shape of the handset, the hardness of fixing devices such as rubber gaskets, and variations in the characteristics of the handset. Since the transmitter of the 601-type telephone uses a carbon microphone that does not require signal amplification means, the sensitivity may vary greatly depending on the tilt of the handset, the magnitude of vibration caused by the diaphragm, etc. Therefore, the transmission level of the frequency multiplexed signal tends to fluctuate depending on the acoustic coupling state and the sensitivity of the transmitter, and stable signal transmission cannot be performed as it is.

Conventionally, for example, an amplifier and a limiter are provided in the transmission path of the frequency multiplexed signal, and the amplifier always amplifies the transmission level of the frequency multiplexed signal by a certain amount to define the lowest level, and the limiter sets the transmission signal level to a predetermined level. The transmission signal level is stabilized by keeping it below the maximum value.

However, in such conventional devices, when the frequency multiplexed signal is limited by a limiter, the frequency components of the audio signal and the data-modulated carrier wave are mixed with each other, resulting in a decrease in the S/N of the transmitted signal. However, there was a problem in that communication quality deteriorated.

(Problems to be Solved by the Invention) As described above, in conventional devices, frequency mixing occurs between the audio signal and the modulated carrier wave of the data due to the limiter that defines the maximum value of the transmitted signal level, and this causes However, the present invention has focused on this problem and is capable of transmitting signals at an optimal signal level at all times, no matter what the acoustic coupling state or the sensitivity of the transmitter is. Moreover, the present invention aims to provide a voice/data multiplexing device that can prevent frequency mixing, reduce S/N, and improve communication quality.

[Configuration of the Invention (Means for Solving Problems)] The present invention comprises a signal level determining means 100 for determining the carrier reception level of a received transmission signal, a notification means 200 for notifying a decrease in the reception level, A transmission level varying means 300 for a transmission transmission signal is provided, and the signal level determining means 1
00 detects the carrier reception level of the received transmission signal introduced via the acoustic coupler and compares this reception level with a preset reference level, and as a result of this comparison it is determined that the reception level does not meet the reference level. In this case, the notifying means 200 notifies the speaker of this fact, and when the speaker performs a predetermined level varying operation, the transmitting level varying means 300 changes the transmission signal of the transmitted transmission signal in response to this operation. The level is variable.

(Function) As a result, if the carrier wave reception level of the transmission signal arriving from the communication partner device is lower than the reference level, this is detected by the signal level determining means 10°0 and the notifying means 20
The speaker is notified by 0.

Then, in accordance with this notification, the speaker informs the other party of the communication through a voice call, and when this speaker operates the transmission level variable means 300, the transmission level variable means 300
This increases the transmission signal and the bell level of the other party's device. Therefore, even if the acoustic coupling state of the other party's device is poor or the sensitivity of the transmitter is reduced, a transmission signal with a sufficiently high transmission signal level will be sent. Also,
Since the transmission signal level can be set to an arbitrary value by the signal level variable means, it can be set to the optimum level each time, and a limiter is therefore unnecessary. Therefore, frequency mixing between the voice signal and the carrier wave is prevented, and this, together with the increase in the transmission signal level, improves communication quality.

(Embodiment) FIG. 2 shows the configuration of an audio/data multiplexing device in an embodiment of the present invention. In this figure, the same parts as those in FIG. 4 are given the same reference numerals and detailed explanations will be omitted.

The modulated carrier wave separated and extracted by the BPF1 7 of the receiving circuit system is introduced into the frequency demodulation circuit 18 and also guided to the reception level detection circuit 21. This reception level detection circuit 21 is composed of a full-wave or half-wave rectification circuit, and outputs a DC voltage corresponding to the reception level of the modulated carrier wave to the level comparison circuit 22. The level comparison circuit 22 converts the detected voltage output from the reception level detection circuit 21 into the battery 23.
When the detected voltage is less than the reference voltage, a drive signal is generated to turn on the light emitting diode 24 as a notification means. Note that the value of the reference voltage is set corresponding to the lowest carrier reception level at which data can be transmitted with a certain error rate or higher. Also,
A variable amplifier circuit 25 is provided between the adder 15 and the acoustic coupler 16 of the transmitting circuit system. The variable amplification circuit 25 changes the degree of amplification according to the amount of operation of the volume control 26, thereby variably setting the transmission signal level of the frequency multiplexed signal.

With such a configuration, the modulated carrier wave of the frequency multiplexed signal separated and extracted by the BPF 17 after reception is demodulated by the frequency demodulation circuit 18 and then led to a monitor device (not shown) for display, and is also displayed by the reception level detection circuit. 21, where the reception level is detected. Then, this detection level is compared with the reference voltage of the battery 23 by the level comparison circuit 22. By the way, if the coupling state of the acoustic coupler to the handset of the other party's device is poor, or if the reception level of the frequency multiplexed signal does not reach the reference voltage due to a decrease in the sensitivity of the transmitter, the level comparison circuit 22 A signal is generated and the light emitting diode 2
4 lights up. Therefore, the speaker can know that the reception level is low by the lighting of the light emitting diode 24. Then, when the speaker verbally informs the speaker on the data transmission side of this through a voice call, and in response, the speaker on the other party operates the volume 26 to increase the amplification degree of the variable amplification circuit 25. The transmission signal level of the frequency multiplexed signal sent from the other party's device is increased, allowing the receiving device to receive carrier waves and audio signals of sufficiently high levels. Incidentally, if the light emitting diode 24 is still not turned off after the - number of operations, the above operation may be repeated several times until the light emitting diode 24 is turned off.

In this way, in this embodiment, the received level of the carrier wave is detected, and when this received level does not reach the reference level, the light emitting diode 24 is turned on to notify that fact, and the transmitted signal level from the communication partner is detected. In order to meet the increasing demand, a variable amplifier circuit 25 is installed in the transmitter circuit system so that the transmit level of the frequency multiplexed signal can be set variably by manual operation, so that the speaker can reliably know that the received level is low. Furthermore, when the other party communicates this over the phone, the transmission level of the frequency multiplexed signal can be easily reset to an appropriate level by simply operating the volume 26. Therefore, even if the acoustic coupling state of the acoustic coupler 16 to the handset 3 is poor or the transmission level of the frequency multiplexed signal is low due to a decrease in the sensitivity of the transmitter, this transmission level can be very easily and reliably adjusted to an appropriate level. This can improve the call quality. In addition, since the transmission level of the frequency multiplexed signal can always be set to the optimum value by the operation amount of the volume 26, there is no need for a limiter to set the maximum value of the transmission level, and as a result, the audio signal band and the modulated carrier band No mixing of frequencies occurs between the two, which makes it possible to reduce the signal-to-noise ratio of the signal and to perform high-quality communication.

Note that the present invention is not limited to the above embodiments. For example, the amplification degree of the variable amplifier circuit 25 may be automatically initialized to a preset value when the device is powered on. In this way, the amplification degree is prevented from being left fixed at a low value, and the problem of unnecessarily high transmission level is eliminated. In addition to the visual display by the light emitting diode 24, means for emitting an alarm or the like may be used as the notification means. In addition, the configurations of the transmission level variable means and signal level determination means, the notification form of the notification means, etc. can be modified in various ways without departing from the gist of the present invention.

[Effects of the Invention] As described in detail above, according to the present invention, the signal level determination means for determining the carrier wave reception level of a received transmission signal, the notification means for reporting a decrease in the reception level, and the The signal level determining means detects the carrier wave reception level of the received transmission signal introduced through the acoustic coupler, and compares this reception level with a preset reference level. When it is determined that the resulting reception level does not meet the reference level, the speaker is notified of this using the notification means, and when the speaker performs a predetermined level varying operation, the above transmission is performed in response to this operation. By varying the level of the transmitted transmission signal using the level variable means, signal transmission can always be performed at the optimal signal level no matter what the acoustic coupling state or the sensitivity of the transmitter is. It is possible to provide a voice/data multiplexing device that can prevent the mixture of signals, increase S/N, and improve communication quality.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a circuit block diagram showing the configuration of an audio/data multiplexing device in an embodiment of the present invention, and FIG. 3 is a carrier wave modulated by audio signals and data. A diagram showing an example of frequency division multiplexing with
FIG. 4 is a circuit block diagram showing the configuration of a conventional audio/data multiplexing device. 1...Telephone body, 2...Telephone line, 3...Handset, 11...Frequency modulation circuit, 12.17...
・Band pass filter (BPF), 13, 16b...
Microphone, 14.19... Band elimination filter (BEF), 15... Adder, 16... Acoustic coupler, 18... Frequency demodulation circuit, 20.16a...
・Speaker, 21... Reception level detection circuit, 22...
・Level comparison circuit, 23...Battery for setting reference voltage,
24... Light emitting diode, 25... Variable amplifier circuit,
26...Volume.

Claims (1)

[Claims] A voice/data multiplexing device comprising an acoustic coupler coupled to a handset of a telephone, and transmitting/receiving a transmission signal obtained by frequency division multiplexing a carrier wave frequency-modulated by data and a voice signal to/from a telephone line via the acoustic coupler. In,
signal level determining means for detecting the carrier reception level of the received transmission signal introduced through the acoustic coupler and comparing the received signal level with a preset reference level; and the signal level determining means determines whether the received signal level is at the reference level. The present invention is characterized by comprising a notification means for notifying the speaker when it is determined that the level is not satisfied, and a transmission level variable means for varying the signal level of the transmitted transmission signal in accordance with a predetermined variable operation. Voice/data multiplexing equipment.