JP2687692B2 - Signal receiving circuit for in-band signal transmission device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-band signal transmission device that uses a frequency within a band as a signal current, and particularly to a band having a function of preventing malfunction of a signal current and a protection function in a receiving circuit. The present invention relates to a signal receiving circuit for an internal signal transmitting device.

[Conventional technology]

Second example of conventional signal reception circuit for in-band signal transmission device
It will be described with reference to FIGS.

In FIG. 2, a delay circuit is added to the protection circuit at a single frequency.

In FIG. 2, 21 is a pass wave filter for f ₁ which passes a signal current having a signal frequency f ₁ , 24 is a f ₁ blocking wave device, and 22 and 25 are f ₁ passing wave devices 21 and f ₁ blocking wave. An amplifier circuit for amplifying each output of the amplifier 24, 23 and 26 are rectifier circuits for rectifying each output of the amplifier circuits 22 and 25, and 27 is a comparison for comparing the output of the rectifier circuit 23 and the output of the rectifier circuit 26. The circuit 28 is a delay circuit connected to the output side of the comparison circuit 27.

Next, the operation of the receiving circuit for the in-band signal transmission device shown in FIG. 2 will be described.

When the signal current of the signal frequency f ₁ is input from the input terminal IN, it is extracted by the pass wave filter 21 for f ₁ , and the extracted signal is amplified by the amplification circuit 22 and then rectified by the rectification circuit 23 to generate a direct current. It becomes a signal and is input to the comparison circuit 27. On the other hand, the signal that has passed through the f ₁ blocking wave device 24, is amplified by the amplifier circuit 25, is rectified by the rectifier circuit 26, and becomes a DC signal is compared by the comparison circuit 27 with the output of the rectifier circuit 23. The signal compared by the comparison circuit 27 is input to the delay circuit 28 at the next stage. This delay circuit 28 processes the compared signals in time. In other words, it is determined whether the signal current is the signal current or the signal current (f ₁ ) component included in the conversation in terms of level and time according to the time length of the signal current of the signal frequency f ₁ . OUT indicates an output terminal.

FIG. 3 shows the case where a signal current (two frequencies) is used.

In FIG. 3, those having the same reference numerals as those in FIG. 2 indicate corresponding portions, and 31 is f ₁ for passing a signal current having a signal frequency f _1.
Use pass-receiver, 34 the signal frequency f ₂ of f ₂ for passing duplexer for passing a signal current, 32 and 35 the f ₁ for passing wave 31
And an amplifying circuit for amplifying the respective outputs of the f ₂ pass wave filters 34, 33 and 36 are rectifying circuits for rectifying the respective outputs of the amplifying circuits 32 and 35, and 37 is a rectifying circuit 33, 36.
AND circuit that inputs each output of
It is a delay circuit connected to the output side of 37.

Next, the operation of the signal receiving circuit for the in-band signal transmitting device shown in FIG. 3 will be described.

The signal flow is the signal frequency input from the input terminal IN.
f ₁ of the signal current is extracted by f ₁ for passing wave 31 only the signal frequency f _1. The extracted signal frequency f ₁ is amplified by the amplifier circuit 32 to a required level in the next stage. Then, the amplified signal frequency f ₁ is rectified by the rectifier circuit 33 to become a DC signal, which is input to the AND circuit 37 at the next stage. On the other hand, the signal current of the signal frequency f ₂ input from the input terminal IN is extracted only by the signal frequency f ₂ by the f ₂ pass wave filter 34. The extracted signal frequency f ₂ is amplified to the level required in the next stage.
Amplified by 35. And the amplified signal frequency f ₂
Is rectified by the rectifier circuit 36 to become a DC signal, which is input to the AND circuit 37 at the next stage.

Then, the AND circuit 37 receives the signal of the system of the f ₁ pass wave filter 31-amplifier circuit 32-the rectifier circuit 33 and the signal of the f ₂ pass wave filter 34-amplifier circuit 35-the rectifier circuit 36 system. Only when it is treated as a signal, it is sent to the delay circuit 38 of the next stage. The delay circuit 38 was used to correct the signal waveform and adjust the time.

[Problems to be solved by the invention]

Since the conventional signal reception circuit for the in-band signal transmission device shown in FIG. 2 uses the one-frequency system, if any _one of the signal frequencies f ₁ is input during busy, it is treated as the frequency for the signal current. There is a problem that it is one of the causes of malfunction on the other side, and there is a problem that it takes time to treat the signal current (f ₁ ) to the other party because it has a delay circuit for preventing malfunction. Atsuta

On the other hand, the conventional signal reception circuit for in-band signal transmission device shown in FIG. 3 has a problem that it malfunctions when the same frequency component as the signal current frequency component arrives because it does not have a protection circuit. However, there was a problem of malfunction (operation by 2nd and 3rd waves) in frequency components generated by signals such as.

[Means for solving the problem]

A signal receiving circuit for an in-band signal transmission device according to the present invention is a band-pass wave device (1) that allows a signal in a voice band to be used to pass and blocks other external noise in an in-band signal transmission device using a voice band. ) And the first signal frequency (f ₁ )
The first wave means (2,3,
4), signal blocking means (5,6,7) for blocking passage of both signal currents of the first signal frequency and the second signal frequency (f ₂ ), output levels of the first wave means and the signal blocking means A first detection circuit (9) composed of a first comparison circuit (8) for comparing and a second wave means (10, 11) for passing only a signal current of a _second signal frequency (f ₂ ). , 12), signal blocking means (5, 6, 7) used in common with the first detection circuit, and second comparing circuit (13) for comparing the output levels of the second wave means and the signal blocking means. A configured second detection circuit (14),
The first detection signal output from the first comparison circuit of the first detection circuit and the second detection signal output from the second comparison circuit of the second detection circuit are input and a logical product signal And a switch setting circuit (16) for selecting and outputting any one of the first detection signal, the second detection signal and the AND signal. .

[Action]

In the present invention, the interference from the unused band is reduced by the bandpass wave device, and during the conversation with the interference wave instantaneously generated in the f ₁ detection circuit and f ₂ detection circuit and f ₁ and f ₂ blocking circuit. Signal frequencies f ₁ and f ₂ separated from the included pseudo signal components are obtained, and as a result, true converted signal currents (f ₁ and f ₂ ) are obtained. Also, because it has a switch setting circuit,
It can be used in various ways.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a signal receiving circuit for an in-band signal transmitting device according to the present invention.

In the figure, reference numeral 1 is a band pass wave filter for preventing interference from external noise, which is a filter for passing the entire used band. 2 is a pass wave filter for f ₁ which passes a signal current of signal frequency f ₁ , 3 is an amplifier circuit for amplifying the output of the pass wave filter 2 for f ₁ , and 4 is a rectifier circuit for rectifying the output of this amplifier circuit 3. 5, f ₁ and f ₂ blocking wave device, 6 an amplifying circuit for amplifying the output of the f ₁ and f ₂ blocking wave device 7, 7 a rectifying circuit for rectifying the output of the amplifying circuit 6, 8 a rectifying circuit 4 is an comparing circuit for f ₁ for comparing the output a of 4 with the output b of the rectifying circuit 7, and these constitute an f ₁ detecting circuit 9.

10 is a pass wave filter for f ₂ that passes a signal current of signal frequency f ₂ , 11 is an amplification circuit that amplifies the output of this pass wave device 10 for f ₂ , and 12 is a rectifier circuit that rectifies the output of this amplification circuit 11. ,
Reference numeral 13 is a comparison circuit for f ₂ which compares the output of the rectifier circuit 12 with the output of the rectifier circuit 7. These are the f ₁ and f ₂ blocking wave devices 5, the amplifier circuit 6 and the rectifier circuit 7 together with the f ₂ detection circuit 14. I am configuring.

The f ₁ detection circuit 9 and the f ₂ detection circuit 14 are circuits for receiving the output of the band pass wave filter 1 as input and receiving two frequencies having the same frequency as the signal current frequency while simultaneously preventing other frequency components. Are configured.

15 is the output d of the comparison circuit 8 for f ₁ in the f ₁ detection circuit 9
An AND circuit which receives the output e of the comparison circuit 13 for f ₂ in the f ₂ detection circuit 14 and 16 is an output d of the comparison circuit 8 for f ₁ and an output f of the AND circuit 15 and a comparison circuit 13 for f _2. A switch setting circuit for switching the output e. The switch setting circuit 16 is connected to the output side of the f ₁ detection circuit 9 and the f ₂ detection circuit 14 and is used at the signal frequency f ₁ depending on the line condition and at the signal frequency f ₂ . A circuit capable of selecting three types of usage forms when used and when used at two frequencies of signal frequencies f ₁ and f ₂ is configured.

Then, the signal reception is performed by selecting one of the first signal frequency, the second signal frequency, and two frequencies within a band having a protection function for the audio signal.

 Next, the operation of the embodiment shown in FIG. 1 will be described.

First, when the signal current of the signal frequency f ₁ is input from the input terminal IN, the signal frequency f ₁ is
And then enters the f ₁ pass wave filter 2 of the f ₁ detection circuit 9. This f ₁
Only the signal frequency f ₁ is extracted by the passing wave device 2 and enters the amplifying circuit 3 at the next stage. The signal frequency f ₁ amplified by the amplifier circuit 3 is rectified by the rectifier circuit 4 and converted into a DC signal, which is then guided to the next-stage f ₁ comparison circuit 8. On the other hand, the signal frequency f ₁ passing through the band pass wave filter 1 enters the f ₁ and f ₂ blocking wave filters 5. The component passing through the f ₁ and f ₂ blocking wave devices 5 is an amplifier circuit 6
And amplified to the required level. The amplified component is rectified by the rectifier circuit 7 into a DC signal, which is guided to the f ₁ comparison circuit 8.

Then, the f ₁ for the comparison circuit 8 compares the components except f ₁ levels and f _1, f ₂ frequencies.

Next, when the signal current is the signal frequency f ₂ from the input terminal IN is inputted, the signal current (f ₂₎ passes through the band pass duplexer 1, f _{2 2} for passing wave device f of the detection circuit 14 Enter 10.
Only the signal frequency f ₂ is extracted by the pass wave filter 10 for f ₂ and enters the amplifier circuit 11 at the next stage. The signal frequency f ₂ amplified by the amplifier circuit 11 is rectified by the rectifier circuit 12 and converted into a DC signal, which is then guided to the next-stage f ₂ comparator circuit 13. On the other hand, the signal current of the signal frequency f ₂ passing through the band pass wave filter 1 enters the f ₁ and f ₂ blocking wave filters 5. The component passing through the f ₁ and f ₂ blocking wave devices 5 is amplified by the amplifier circuit 6 and amplified to a required level. The amplified component is rectified by the rectifier circuit 7 into a DC signal, which is guided to the f ₂ comparison circuit 13.

More specifically, the signal frequencies f ₁ and f ₂ are applied to the input terminal IN, enter the band pass wave device 1, and are branched to the f ₁ detection circuit 9 and the f ₂ detection circuit 14. Then, in the f ₁ detection circuit 9, the f ₂ signal component is removed and the output a of the rectification circuit 4 is obtained. Since the other is added to the f ₁ and f ₂ blocking circuits 5, the output b of the rectifying circuit 7 becomes almost “0”. Thus, looking at the f ₁ detection circuit 9, when the signal current f ₁ is inputted to the input terminal IN, the output a of the signal current f ₁ which has passed through the f ₁ for passing duplexer 2 is a positive predetermined level Although it becomes a voltage, since the output level of the output b is almost "0", the output a remains the output d
Becomes However, when the disturbance occurs instantaneously including the frequency components of the signal frequency f ₁ be in the band is inputted, after this disturbance is that has passed through the band pass duplexer 1, the components of f ₁ is f ₁
Passing through the wave pass filter 2 for use as the output a and the comparator circuit 8 for f ₁
The frequency components other than the f ₁ component (excluding the f ₂ component) also pass through the blocking wave device 5 and become the output b, which is also input to the comparison circuit 8 for f ₁ . Therefore, the levels of both signals are almost the same, and the output d including f ₁ is not output. Also, if the call signal contains the component of f ₁ , this
There were to be erroneously detected by detecting the component of f _1, components of f ₁ of the signal in this circuit is input to the f ₁ for comparison circuit 8 as output a passes through the f ₁ for passing duplexer 2 , The frequency components other than the f ₁ component of the signal (excluding the f ₂ component) pass through the blocking wave device 5 and become the output b, which is input to the comparison circuit 8 for f ₁ .
The levels of both signals are almost the same, and the output d including f ₁ is not output.

The operation of the f ₂ detection circuit 14 is exactly the same.

When the output d of f ₁ comparison circuit 8 which positive voltage is generated, also a similar operation to f ₂ detection circuit 14, f ₂ comparison circuit
A positive voltage is generated at the output e of 13 and the output d of the comparison circuit 8 for f ₁ and the output e of the comparison circuit 13 for f ₂ are input to the logical product circuit 15, and the logical product f of these two signals is 1 ”is output.

This state is called a signal receiving state. When _one of the signal frequencies f _{1 and} f ₂ is applied to the input terminal IN, the output d of the comparison circuit 8 for f ₁ and the output e of the comparison circuit 13 for f ₂
Since one of them becomes "0", the output f of the AND circuit 15 becomes "0".

The signal that has passed through this AND circuit 15 is the switch setting circuit 16
to go into. This switch setting circuit 16 sets (a) setting to C and I.
Shows the case of using the band pass wave filter 1 and the f ₁ detection circuit 9 when they are connected. (B) The case where the setting is in contact with C and III, the case where the band pass wave filter 1 and the f ₂ detection circuit 14 are used is shown. Then, the case (c) where C and II are in contact with each other is used when the above (a) and (b) are combined (two frequencies).

〔The invention's effect〕

As described above, the present invention has an effect that interference from a band that is not used can be reduced by providing the bandpass wave device that is used. Further, by including the f ₁ detection circuit, the f ₂ detection circuit, and the f ₁ and f ₂ blocking wave devices, the interfering wave that is generated instantaneously and the signal frequencies f ₁ and f ₂ that are separated from the pseudo signal component included in the call Has the effect that a true converted signal current (f ₁ , f ₂ ) is obtained as a result,
Further, since the switch setting circuit is provided, it can be used in various ways, such as when it is used at f ₁ time, when it is used at f ₂ time, and when it is used at 2 frequencies of f ₁ and f ₂ . Also, as the protection circuit, the f ₁ and f ₂ blocking waves, the amplifier circuit and the rectifier circuit are shared by the f ₁ detection circuit and the f ₂ detection circuit, so the number of circuit components can be small, so it is economical and labor saving. Therefore, there is an effect that the circuit is efficiently used. Further, since it is composed of a simple circuit, it has an effect of being easy to manufacture.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a signal receiving circuit for an in-band signal transmission device according to the present invention, FIG. 2 is a block diagram showing an example of a conventional signal receiving circuit for an in-band signal transmission device, and FIG. FIG. 6 is a block diagram showing another example of a conventional signal receiving circuit for an in-band signal transmission device. 1 ...... bandpass duplexer, 2 ...... f ₁ passage duplexer, 3 ......
Amplifying circuit, 4 ... Rectifying circuit, 5 ... f ₁ , f ₂ blocking wave device,
6 ... Amplifier circuit, 7 ... Rectifier circuit, 8 ... f ₁ comparator circuit, 9 ... f ₁ detection circuit, 10 ... f ₂ pass wave filter, 11 ...
Amplification circuit, 12 …… Rectifier circuit, 13 …… Comparison circuit for f ₂ , 14…
… F ₂ detection circuit, 15 …… AND circuit, 16 …… Switch setting circuit.

Claims (1)

(57) [Claims] 1. An in-band signal transmission device using a voice band, wherein only a band-pass wave filter that passes a voice band signal to be used and blocks other external noise and a signal current having a first signal frequency are used. Through a first wave means, a signal blocking means for blocking the passage of both signal currents of a first signal frequency and a second signal frequency, and a first comparing the output levels of the first wave means and the signal blocking means. And a second detection circuit configured to include only a signal current having the second signal frequency.
And a second detection circuit composed of the second blocking circuit for comparing the output levels of the second wave means and the signal blocking means. , Inputting a first detection signal output from the first comparison circuit of the first detection circuit and a second detection signal output from the second comparison circuit of the second detection circuit, A logical product circuit that outputs a logical product signal; and a switch setting circuit that selects and outputs any one of the first detection signal, the second detection signal, and the logical product signal. Signal receiving circuit for in-band signal transmission device.