JPH07240783A - Transmission/reception level adjusting device - Google Patents

Abstract

PURPOSE:To always perform transmission/reception satisfactorily in spite of ambient noise quantity by changing a coefficient used in an arithmetic operation via a coefficient change means when the levels of transmitted and received signals are detected, respectively and the gain of a corresponding amplifier means is calculated. CONSTITUTION:The levels of the transmitted and received signals of systems on reception and transmission sides are detected by a reception level detecting means and a transmission level detecting means, respectively. The gains of a reception side amplification means and a transmission side amplification means can be decided by the arithmetic operation using a required coefficient by an arithmetic means based on those detected results. When such arithmetic operation is performed, detected reception and transmission levels are compared with a reference value, respectively, and an appropriate coefficient via the coefficient change means based on a compared result is used, which enables the transmission/reception to be always performed satisfactorily in spite of the ambient noise quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission / reception level adjusting device for adjusting a signal level of a transmission / reception signal by appropriately setting amplification gains of the transmission signal and the reception signal in various communication devices such as a telephone.

[0002]

2. Description of the Related Art Conventionally, it has been considered that a communication device such as a hands-free telephone is provided with the following transmission / reception level adjusting device for adjusting the signal level of a transmission / reception signal. For example, transmission level detection means for extracting a transmission signal from the transmission side system and detecting the signal level thereof,
A receiving level detecting means for extracting the receiving signal from the receiving side system and detecting the signal level, a transmitting side amplifying means for amplifying the transmitting signal with a set gain, and an amplifying the receiving signal with the set gain. A receiving side amplifying means, a calculating means for performing a predetermined calculation based on the signal levels of the detected transmitting signal and the receiving signal, and setting a gain of the transmitting side amplifying means and the receiving side amplifying means; That is the device with.

In this type of device, for example, when the signal level of the transmission signal exceeds a predetermined threshold value, it is judged that the transmission is in progress, and the gain of the transmission side amplification means is set to the gain of the reception side amplification means. When the level of the received signal exceeds the threshold value, on the contrary, it is judged that the receiving signal is being received, and the gain of the receiving side amplifying means is set to a large value. For this reason, it is possible to perform good transmission and reception while preventing howling.

[0004]

However, in this type of apparatus, various coefficients such as the threshold value of the signal level used by the arithmetic means are fixed. For this reason,
The following problems occurred. For example, when talking with a small voice in a quiet environment, such as when talking from a home telephone at midnight, the sending signal does not exceed the threshold value, the judgment of the receiving call continues, and it is good for the other party. Could not be sent to. On the other hand, when sending out loud in a noisy environment such as at a construction site, the sending signal always exceeds the threshold value, and the judgment during sending is continued and the other party's talk is improved. There was a possibility that I could not listen.

Particularly, in a hands-free telephone for automobiles, the amount of noise around the telephone greatly changes due to opening and closing of windows, running and stopping of the vehicle, and the like. Therefore, there is a possibility that transmission or reception may suddenly become unsatisfactory. For example, if the amount of noise around the telephone suddenly increases by opening a window during reception, the calculation means may determine that the transmission has been switched, and the reception sound may be interrupted.

Therefore, the present invention has been made for the purpose of providing a transmission / reception level adjusting device capable of always executing excellent transmission / reception regardless of the amount of noise in the surroundings.

[0007]

In order to achieve the above object, the invention according to claim 1 takes out a transmission signal from a transmission side system and detects its signal level, as illustrated in FIG. Transmitting level detecting means, receiving level detecting means for extracting the receiving signal from the receiving side system and detecting the signal level, transmitting side amplifying means for amplifying the transmitting signal with a set gain, and the receiving signal Of the transmitting side amplifying means and the receiving side amplifying means by performing a predetermined calculation based on the detected transmitting signal and the signal level of the receiving signal. A transmission / reception level adjusting device, comprising: a transmission / reception level adjusting device including a calculation unit for setting a gain; and a coefficient changing unit for changing a coefficient used in the calculation.

According to a second aspect of the present invention, when the signal level of one of the transmission signal and the reception signal exceeds a predetermined threshold value, the calculation means exceeds the threshold value. The gains of the transmitting side amplifying means and the receiving side amplifying means are set so that the gain on the other side is larger than the gain on the other side, and the coefficient changed by the coefficient changing means is the threshold value. The transmission / reception level adjusting device according to claim 1 is characterized in that it is present.

Further, the invention according to claim 3 provides the transmission / reception level adjusting device according to claim 1, wherein the coefficient changing means changes the coefficient stepwise.

[0010]

According to the present invention having the above-described structure, the coefficient changing means can change the coefficient used for the calculation executed by the calculating means. Therefore, the coefficient can be changed according to the ambient noise amount. It can be a different value. Then, using the coefficient thus changed, the calculation means
A predetermined calculation is executed based on the signal levels of the transmitting signal and the receiving signal to set the gains of the transmitting side amplifying means and the receiving side amplifying means. Therefore, the gain of each amplification means is appropriately switched according to the transmission or reception.

According to the second aspect of the present invention, the calculating means, when the signal level of one of the transmission signal and the reception signal exceeds a predetermined threshold value, the gain on the side exceeding the threshold value. Is set to be larger than the gain on the other side, the gains of the transmitting side amplifying means and the receiving side amplifying means are set. Therefore, when the received signal is input and the signal level exceeds the threshold value, the gain of the receiving side amplifying means is made larger than the gain of the transmitting side amplifying means, and good reception is possible. Further, when the transmission signal is input and the signal level exceeds the threshold value, the gain of the transmission side amplifying means is made larger than the gain of the reception side amplifying means, and good transmission is possible.

Moreover, the coefficient changing means changes the threshold value. Therefore, if the signal level of the received signal or the transmitted signal does not exceed the threshold value during receiving or transmitting, the threshold value is changed to a lower value, and the transmitting signal or receiving signal If the signal level exceeds the threshold value, the threshold value can be changed to a higher value.

Further, according to the invention of claim 3, the coefficient changing means changes the coefficient stepwise. Therefore, the coefficient selection operation becomes easy.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a telephone 1 of an embodiment to which the invention described in claims 1 to 3 is applied. The telephone 1 according to the present embodiment includes a telephone body (hereinafter referred to as a cradle) 3 fixed between a driver's seat and a passenger seat of an automobile, and a handset telephone handset detachably provided in the cradle 3. (Hereinafter referred to as "handset") 5 and a wireless telephone 7 which communicates with other telephones as a main part. In addition, the telephone 1 has a so-called hand-free call function that enables transmission and reception with the handset 5 still attached to the cradle 3.
In FIG. 1, only the configuration of the part related to hands-free communication is shown.

As shown in FIG. 1, the wireless device 7 inputs the received reception signal to the handset 5. The reception signal input to the handset 5 is sequentially input to the cradle 3 via the amplifier 11, the variable gain amplifier 13, and the amplifier 15. The received signal input to the cradle 3 is the amplifier 3
1, output as voice through the speaker 33 for hands-free communication.

The cradle 3 includes a microphone 35 for converting a user's voice into an electric signal (sending signal), and the microphone 3
And an amplifier 37 for amplifying the transmission signal output from the handset 5 and inputting it to the handset 5. The transmission signals input from the amplifier 37 to the handset 5 are sequentially transmitted to the amplifier 4
1, the variable gain amplifier 43, and the radio 45 via the amplifier 45
Entered in. Then, the wireless device 7 transmits the input transmission signal to another telephone. The amplifiers 11 and 1
Reference numerals 5, 31, 37, 41, and 45 are fixed gain amplifiers each having a fixed gain.

Next, the handset 5 is provided with an electronic control circuit (ECU) 51 as a calculation means for setting the gains of the variable gain amplifiers 13 and 43. In addition, the electronic control circuit 51 outputs the output of the amplifier 11 to the reference voltage generation circuit 53.
Of the output voltage of the amplifier 41, a comparator 59 of comparing the output of the amplifier 41 with the output voltage of another reference voltage generating circuit 57, and a threshold value and a delay time described later according to the user's operation. , And a change-over switch 61 as a coefficient changing means for changing over the attenuation amount and the like.

The reference voltage generating circuits 53 and 57 generate two kinds of reference voltages, large and small, according to the signal from the electronic control circuit 51. The comparators 55 and 59 output the amplifiers 11 and 41. It outputs a negative pulse to the electronic control circuit 51 when the voltage exceeds the voltage generated by the reference voltage generation circuits 53 and 57. That is, the comparator 55 serves as a receiving level detecting means, and the comparator 59 serves as a transmitting level detecting means.
Equivalent to each. Further, the changeover switch 61 has three push button switches (not shown) for instructing the switching of the threshold value, the delay time, or the attenuation amount, and inputs the operation state thereof to the electronic control circuit 51.

In the telephone 1 constructed in this way, the electronic control circuit 51 uses the gain of the variable gain amplifier 13 as the receiving side amplifying means when receiving, and the gain of the variable gain amplifier 43 as the transmitting side amplifying means during transmitting. Are set to be larger than the gain of the other variable gain amplifier 43 or 13, respectively, and the transmission / reception level adjustment processing for adjusting the signal level of the transmission / reception signal is executed. Next, the transmission / reception level adjustment process will be described with reference to the flowchart of FIG. It should be noted that the electronic control circuit 51 executes this processing at a predetermined cycle when the wireless device 7 connects the telephone 1 to the line of another telephone.

When the processing is started, first, step 101
It is determined whether or not the changeover switch 61 has been pressed.
When the switch is pressed, the process proceeds to step 103, 105, or 107 depending on which of the switches instructing the change of the damping force, the threshold value, or the delay time, and when not operated, The process directly proceeds to step 111.

A changeover switch 61 for instructing to change the damping force
When is pressed and the process proceeds to step 103, the change amounts of the amplification factors of the variable gain amplifiers 13 and 43 at the time of receiving and transmitting are switched as follows. When this change amount is set to 20 dB, it is set to 10 dB, and when it is set to 10 dB, it is set to 20 dB.

Step 10 is instructed to change the threshold value.
When shifting to 5, the voltage generated by the reference voltage generating circuits 53 and 57 (hereinafter referred to as the threshold value S) is switched between two types, large and small. That is, when the threshold value S is set to a larger value, it is set to a smaller value, and when it is set to a smaller value, it is set to a larger value.

Step 10 is instructed to change the delay time.
When shifting to 7, the delay times T1 and T2 are switched to two types, long and short, as follows. That is, each delay time T1, T2
Is set to 200 ms when is 0 ms, and is set to 0 ms when is 200 ms. As will be described later, the delay time T1 corresponds to the release time on the transmitting side and the attack time on the receiving side, and the delay time T2
Corresponds to the attack time on the transmitting side and the release time on the receiving side.

Subsequently, at step 111, it is judged based on the output of the comparator 55 whether or not the output of the amplifier 11 (hereinafter referred to as the reception level) is larger than the threshold value S. When the receiving level is> S (step 111: Y
ES) judges that the call is being received, and shifts to the processing of steps 113 to 117 described below. Also, the listening level ≤
In the case of S (step 111: NO), directly step 12
Move to 1.

When it is judged that the voice is being received and the routine proceeds to step 113, the above-mentioned delay time T1 is waited, and then the gain (receive gain) of the variable gain amplifier 13 is set to the lower one which is determined according to the attenuation amount. The value (step 115) and the gain (transmission gain) of the variable gain amplifier 43 are set to the higher value determined according to the attenuation amount (step 117), and the process proceeds to step 121.

Then, in 121 to 127, similarly, it is judged based on the output of the comparator 59 whether or not the output of the amplifier 41 (hereinafter, referred to as a transmission level) is larger than the threshold value S ( If the transmission level> S (step 121), (step 121: YES), it is determined that the transmission is in progress, and the processes of steps 123 to 127 are executed. That is, after waiting for the delay time T2 (step 123), the transmission gain is set to a low value (step 125) and the reception gain is set to a high value (step 127), and the processing is temporarily terminated. When the transmission level ≦ S (step 121: N
O) ends the process as it is.

Therefore, the telephone 1 of this embodiment can process the transmission signal and the reception signal as follows. That is, when the reception signal is input and the reception level exceeds the threshold value S (step 111: YES), the gain of the variable gain amplifier 13 on the reception side is reduced to a low value after the delay time T1 (step 115), and the signal is transmitted. Variable gain amplifier 4 on the talk side
The gain of 3 can be set to a high value (step 117), and good reception can be achieved. When the transmission signal is input and the transmission level exceeds the threshold value S (step 121: YES), the gain of the variable gain amplifier 43 on the transmission side is set to a low value after the delay time T2 (step 12).
5), the gain of the variable gain amplifier 13 on the receiving side can be set to a high value (step 127), respectively, and good speech can be transmitted.

Moreover, the threshold value S can be switched between two types, large and small, by a simple operation of depressing the push button of the changeover switch 61. Therefore, when the listening level or the speaking level is equal to or lower than the threshold value S while receiving or transmitting, for example, when speaking in a quiet voice in a quiet environment.
If the value does not exceed the threshold value, the threshold value S is made smaller, and if the talk level or the talk signal level exceeds the threshold value S during the listening or during the talking, as when loudly speaking in a noisy environment. The threshold can be increased.
Therefore, the threshold value S may be set such that only the reception level during the reception and the transmission level during the transmission exceed the threshold S irrespective of the ambient noise amount. it can.

Then, an affirmative judgment is made in step 111 and a negative judgment is made in step 121 during the reception of a voice, and a negative judgment is made in step 111 and a positive judgment is made in the step 121 during transmission. become. As a result, it is possible to surely execute the control of setting the gain of the variable gain amplifier 13 during the reception of a voice and the gain of the variable gain amplifier 43 during the transmission, respectively, to be larger than the gain of the other, so that the noise around the surroundings can be surely executed. Regardless of the amount, good transmission / reception can be always performed.

Here, FIG. 3 shows that the threshold value S is changed,
9 is a time chart showing changes in the determination result in step 111. As illustrated in the figure, the changeover switch 61
Each time there is an input from, the threshold value S has two kinds of values (S1, S2) in synchronization with the fall of the input signal (a).
). Therefore, use threshold S2 if the listening level (c) does not fall below S1 even during a call, and use threshold S1 if the listening level does not rise above S2 during a call. With this, it is possible to perform transmission / reception satisfactorily. Further, since the threshold value S is switched alternately between S1 and S2 in a stepwise manner, it is very easy to select the threshold value S, and the telephone 1
It is possible to prevent the driver from being forced to perform a complicated operation while driving a vehicle equipped with.

In this embodiment, the delay times T1 and T2 are
Similarly, by operating the selector switch 61, it is possible to switch between long and short two types of values. FIG. 4 is a time chart showing a change in the judgment result in step 111 due to the change of the delay time. As illustrated in (d), when the delay time is set to be short (T1, T2 = 0 ms), whether or not the reception level exceeds the threshold value S is immediately reflected in the determination result. Therefore, the responsiveness of transmission and reception is improved.

Further, as shown in (e), when the delay time is set to be long (T1, T2 = 200 ms), whether or not the reception level exceeds the threshold value S is reflected in the judgment result with a delay. . Further, since the change in the listening level during the delay time (here, T1) is ignored, the judgment of YES continues even if the listening level may fall below the threshold value S, as illustrated in (e). It may be done. Therefore, it is possible to favorably prevent the transmission / reception gain from frequently changing and causing noise such as patter.

Then, as illustrated in (f), the delay times T1 and T2 can be set to long or short by operating the changeover switch 61.
If the type is changed, the change in the judgment result also changes accordingly. Therefore, by selecting the delay time times T1 and T2 according to the ambient noise condition and the like, it is possible to always carry out good transmission and reception.

Further, if the amount of attenuation is increased, the change in gain between transmitting and receiving becomes large and the effect of the above gain control becomes more remarkable, and if the amount of attenuation is decreased, the change in gain becomes smaller. The feeling of strangeness is reduced. The delay times T1 and T2 and the attenuation amount can be switched by a simple operation using the push button of the changeover switch 61.

The present invention is not limited to the above-mentioned embodiments, but can be carried out in various modes without departing from the gist of the present invention. For example, in the above embodiment, the threshold value S, the delay times T1 and T2, and the attenuation amount are configured to be switchable, but it is also possible to switch any one of these, and further The coefficient may be switched. Further, the threshold S, the delay times T1 and T2, and the coefficients such as the attenuation amount may be steplessly switched by a dial or the like. In this case, although the operation is slightly complicated as compared with the above embodiment, each coefficient can be set to a desired value.

Further, in the above embodiment, the coefficient such as the threshold value S is changed according to the operation of the changeover switch 61.
You may comprise so that these coefficients may be changed automatically. For example, the cradle 3 is provided with a sensor as a noise detecting means for detecting the ambient noise amount, and the threshold value S is increased when the noise amount detected by the sensor is large and the threshold value is increased when the noise amount is small. S may be set small. In this case, good transmission / reception can be automatically executed regardless of the amount of noise in the surroundings.

Furthermore, in the above embodiment, the transmission level and the reception level are compared with the threshold value S, and the gains of the variable gain amplifiers 13 and 43 on the side exceeding the threshold value S are increased. The present invention can also be applied to a communication device that compares the reception level with the transmission level and increases the gains of the variable gain amplifiers 13 and 43 on the higher side. For example, in such a communication device, when the difference between the reception level and the transmission level becomes equal to or more than a predetermined value, the magnitude of the gain may be changed so that the gain change has a hysteresis characteristic. The predetermined value, which serves as a reference for changing the gain, can be configured to be switched by a switch operation. In this case, when the ambient noise is large and the gain is changed by the noise, the predetermined value is increased to make it difficult to change the gain, or when the ambient noise is small, the predetermined value is changed. Can be reduced to improve the response of the gain change.

[0038]

As described in detail above, in the invention according to claim 1, since the coefficient used for the calculation can be changed to a value according to the ambient noise condition, etc., it is set by the calculation means. The gains of the transmitting side amplifying means and the receiving side amplifying means can be appropriately switched according to the transmitting or receiving side. Therefore, regardless of the amount of noise in the surroundings, good transmission / reception can always be performed.

According to the second aspect of the present invention, when the signal level of the received signal or the transmitted signal does not exceed the threshold value during reception or transmission, the threshold value is changed to a low value, and reception or transmission is performed. If the signal level of the transmission signal or the reception signal exceeds the threshold value even during the talk, the threshold value can be changed to a higher value. Therefore, regardless of the amount of ambient noise,
The thresholds can be set so that only the signal level of the received signal exceeds the threshold during reception and only the signal level of the transmitted signal during transmission.

Then, the calculating means obtains the gain of the receiving side amplifying means during the reception, and the gain of the transmitting side amplification means during the transmission.
Since the gain is set to be larger than the gain of the other amplifying means, good transmission / reception can always be performed regardless of the amount of ambient noise. Further, in the invention according to claim 3, the coefficient changing means changes the coefficient stepwise, thereby facilitating the coefficient selecting operation. Therefore, it is possible to reduce the manufacturing cost of the device and prevent the user from requiring complicated operations. Therefore, when applied to, for example, a telephone for an automobile, the driver does not need to perform complicated operations while driving, and good transmission and reception can be realized by simple operations.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a telephone according to an embodiment.

FIG. 2 is a flowchart showing a transmission / reception level adjustment process according to the embodiment.

FIG. 3 is a time chart showing a change in the determination result according to the threshold value change of the embodiment.

FIG. 4 is a time chart showing a change in the determination result according to the change of the delay time according to the embodiment.

FIG. 5 is a structural example of the present invention.

[Explanation of symbols]

1 ... Telephone 3 ... Cradle 5 ... Handset 7 ... Radio 13,43 ... Variable gain amplifier 33 ...
Speaker 35 ... Microphone 51 ... Electronic control circuit 53,
57 ... Reference voltage generating circuit 55, 59 ... Comparator 61 ... Changeover switch

Claims (3)

[Claims] 1. A transmission level detecting means for extracting a transmission signal from a transmission side system and detecting the signal level thereof, and a reception level detecting means for extracting a reception signal from the reception side system and detecting the signal level thereof. A transmitting side amplifying means for amplifying the transmitting signal with a set gain, a receiving side amplifying means for amplifying the receiving signal with a set gain, and a signal level of the detected transmitting signal and receiving signal. In the transmission / reception level adjusting device, the transmission / reception level adjusting device includes a calculation unit configured to execute a predetermined calculation based on the calculation unit to set the gains of the transmission-side amplification unit and the reception-side amplification unit, and change the coefficient used for the calculation. A transmission / reception level adjusting device comprising coefficient changing means. 2. When the signal level of one of the transmitted signal or the received signal exceeds a predetermined threshold value, the computing means has a gain on the side exceeding the threshold value of the other signal. The gains of the transmitting side amplifying means and the receiving side amplifying means are set so as to be larger than the gain of the transmitting side, and the coefficient changed by the coefficient changing means is the threshold value. 1. The transmission / reception level adjusting device according to 1. 3. The transmission / reception level adjusting device according to claim 1, wherein the coefficient changing means changes the coefficient stepwise.