JPH02127808A - Automatic sound volume adjusting device in on-vehicle acoustic equipment - Google Patents

Abstract

PURPOSE:To able to listen to a traffic information broadcast in nearly the same sound volume on the listening sense independently of drive noise by storing a value being the result of subtracting a sound volume compensation quantity from a sound volume just before the end of reception and controlling the gain so as to obtain a sound volume in response to the value of adding the sound volume compensation quantity to the stored value at the reception. CONSTITUTION:Four kinds of sources such as an FM tuner 1 are provided and L, R audio outputs of the tuner 1 are selected by a switch circuit 5 and fed to a speaker via a gain variable circuit 6. On the other hand, a detection output by a noise detection section 24 such as vehicle drive noise is a input to be subtracted of a subtractor 23. Then a value being the result of subtracting the sound volume just before the end of reception of a traffic information broadcast from the sound volume compensation quantity in the reception is stored and the gain of the gain variable circuit 16 is controlled so as to obtain the sound volume in response to the addition of the sound volume compensation quantity to the stored value. Thus, the traffic information broadcast is listened to in nearly the same sound volume on the listening sense independently of the drive noise.

Description

TECHNICAL FIELD The present invention relates to an automatic volume adjustment device, and more particularly to an automatic volume adjustment device for a vehicle-mounted audio device equipped with a receiving device capable of receiving traffic information broadcasts.

BACKGROUND ART There is a traffic information broadcasting system called the AR1 system that broadcasts traffic information on a time-division basis during the program broadcast of a general broadcasting station to provide a service to listeners of in-vehicle audio devices such as car radios. be.

This traffic information broadcast is carried out by, for example, an FM broadcast station, but it is not carried out by all FM broadcast stations, but by some specific stations. For this reason, this particular station has a 57KHz subcarrier as a traffic information station identification signal (hereinafter referred to as SK double signal) that indicates that it is a station that broadcasts traffic information, and this is frequency modulated to the main carrier. Since the receiver is transmitting, this SK
Depending on the presence or absence of double signal detection, it is possible to distinguish between stations that broadcast traffic information and stations that do not.

When broadcasting traffic information, the information is generally sent as monaural with only the main signal component, but 57K
SK double signal of H2, area identification signal to indicate which area the traffic information is information on (hereinafter referred to as BK double signal)
and an announcement identification signal (hereinafter referred to as the DK double signal) that informs that traffic information is being broadcast. Frequency of 1/integer of BK double signal 57KHz (23.75Hz ~ 53.98Hz
), and is a single tone DK multiplied signal of 125 Hz.

Traffic information announcements are broadcast, for example, about four times an hour during general program broadcasts, each time lasting a few minutes. On the receiver side, the subcarrier of 57KHz (S
By detecting the 125H2 DK double signal, which is amplitude modulated from the K double signal, only when this DK double signal is present, traffic information can be output at an appropriate volume even if the volume is set to low, and it can also be used to output traffic information at an appropriate volume even when the volume is set to low. In a car-mounted audio device equipped with other sources such as a player, it is possible to automatically preferentially listen to traffic information by detecting the DK double signal even while the player is playing.

In an in-vehicle audio device equipped with a traffic information receiving device that receives broadcasts from such a traffic information system, traffic information is output at an appropriate volume by detecting the DK double signal as described above. Because the volume was fixed at a preset level, when the driving noise is very loud, such as when driving on a cobblestone road, if the set level is low, the output sound of traffic information will be affected by the driving noise. There are cases where you may miss hearing due to masking. Also,
On the other hand, if the set level is raised, the output sound of traffic information will be too loud even when the driving noise is low, causing discomfort to the listener.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic volume adjustment device for a vehicle-mounted audio device that allows traffic information broadcasts to be heard at approximately the same volume regardless of running noise.

The automatic volume adjustment device according to the present invention is an in-vehicle audio device equipped with a receiving device capable of receiving traffic information broadcasting, and has a variable gain circuit that manually receives audio signals, and adjusts the signal levels of the noise signal and the audio signal. The automatic volume adjustment device adjusts the volume by determining a volume compensation amount based on the compensation amount and controlling the gain of the variable gain circuit according to the compensation amount, and the automatic volume adjustment device adjusts the volume by controlling the gain of the variable gain circuit according to the compensation amount. The gain of the variable gain circuit is controlled so that a value obtained by subtracting the volume compensation rriW in the middle is stored, and the volume becomes a value corresponding to the value obtained by adding the volume compensation amount to the stored value when receiving the traffic information broadcast. It has become.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, the in-vehicle audio device according to the present invention is equipped with four types of sources: an FM tuner 1, an AM tuner 2, a cassette player 3, and a CD player 4, and the LR audio output of one of these sources is switched The signal is selected by a circuit 5, and is supplied to a speaker (not shown) via a variable gain circuit 6, which includes, for example, an electronic volume. Source selection by the switch circuit 5 is made by the system controller 7.

The F lvl tuner 1 includes a front end that converts radio waves received by an antenna 8 into an intermediate frequency (IF), a band pass filter 10 that passes the intermediate frequency from this front end 9, and an intermediate frequency from this band pass filter 10. an IF detection section 11 that performs frequency amplification detection;
It has a well-known circuit configuration comprising a noise canceling/multiplexing (~1PX) section 12 that reduces noise from the output of the IF detection section 11 and performs stereo decoding.

The SDK system 13 is for controlling the reception of traffic information based on the output of the IF detection unit 11, and is used to control the reception of traffic information based on the output of the IF detection unit 11, and is used to identify the SK multiplied signal, the BK multiplied signal, and the DK multiplied signal.
K decoder 14, BK decoder 15 and DK decoder 1
It is mainly composed of 6. The SK decoder 14 is
57 of the subcarrier with the SK multiplied signal from the output of the F detection section 11
Detection is performed at a high frequency of KHz. BK decoder 15 is SK
The BK multiplied signal frequency is detected from the output of the decoder 14 to determine the region. Further, the DK decoder 16 detects a 125 Hz DK multiplied signal from the output of the SK decoder 14, and determines whether traffic information is being broadcast. Each output of these decoders 14 to 16 is input to the system controller 7.

The R audio output is also supplied to the signal detection section 17 via the variable gain circuit 6 . The signal detection unit 17 includes an adder 18 that adds the L and R audio outputs, and an adder 18 that adds the L and R audio outputs.
a variable gain circuit 19 consisting of, for example, an electronic volume, which performs gain control on the addition output of the variable gain circuit 19;
a detection/smoothing circuit 20 that detects and smoothes the output of the detection/smoothing circuit 20, and a logarithmic compression circuit 2 that logarithmically compresses the output of the detection/smoothing circuit 20.
1, and a time constant circuit 22 which uses the output of the number compression circuit 21 as a human power. This signal detection section 1
The detection output of 7 becomes the subtraction input of the subtracter 23.

On the other hand, a noise detection section 24 is provided for detecting noise such as vehicle running noise, and the detection output of this noise detection section 24 becomes the subtracted input of the subtractor 23. Noise detection section 24
The microphone 25 detects external noise, the amplification/A wave filter 26 amplifies the detection output of the microphone 25 and extracts and outputs only the noise band component, and the output of the amplification/filter 26 is detected and smoothed. It is composed of a detection/smoothing circuit 27, a logarithmic compression circuit 28 that logarithmically compresses the output of the detection/smoothing circuit 27, and a time constant circuit 29 that uses the output of the logarithm compression circuit 28 manually.

The subtracted output of the subtracter 23 is supplied to a binary encoder 30 having a comparator function. The binary encoder 30 has a comparison reference value, and supplies the difference between the subtraction output of the subtracter 23 and the comparison reference value to the variable gain circuit 19 of the signal detection section 17 as a gain control signal, and also outputs the difference to the binary code. It is converted into digital data and supplied to the system controller 7 as gain control data. The variable gain circuit 19 of the signal detection section 17 is provided to perform stable signal detection by canceling the level change of the signal detection input due to the gain control of the variable gain circuit 6 based on the detection output of the noise detection section 24. It is something that

The system controller 7 is composed of a microcomputer, and performs various controls according to key operation commands on the keyboard section 31, generates source control signals for the AM tuner 2, cassette player 3, and CD player 4, and controls the binary encoder 30. Gain control of the variable gain circuit 6 according to gain control data from the controller, setting of the comparison reference value of the comparator in the binary encoder 30, each of the time constant circuit 22 of the signal detection section 17 and the time constant circuit 19 of the noise detection section 24. Performs control such as time constant setting.

Next, the automatic volume adjustment processing procedure executed by the processor of the system controller 7 will be explained according to the flowchart of FIG.

First, the processor stores a value preset at the time of shipment as the volume when receiving traffic information broadcasts (hereinafter referred to as DK volume) in internal register I, and also internally stores an initial value O as the volume compensation amount for automatic volume adjustment. Step SL) to store each in the register ■, and then the binary encoder 30
(step S2), and compares this gain control data with the volume compensation amount data (initial value is 0) for the variable gain circuit 6 to determine whether or not there has been a change in the volume compensation amount ( Step S3).

If there is a change in the volume compensation amount, it is determined whether the attenuation amount in the variable gain circuit 6 (hereinafter referred to as VR attenuation amount) is - flash, that is, whether the electronic volume is at the minimum (step S4).
, --, if not, set the new VR attenuation amount to be the attenuation amount plus the change in the volume compensation amount (Step S5)
Then, the volume compensation amount is updated by storing the change in the internal register (2) (step S6).

If it is determined in step S3 that there is no change in the volume compensation amount, or after the volume compensation amount is updated in step S6, the SD
By monitoring the DK double signal detection output from the DK decoder 16 in the K system 13, it is determined whether or not an interruption of traffic information broadcasting (hereinafter referred to as DK interruption) has started (step S7); if the interruption has not started, step S7) S
Return to step 2 and repeat the above process. If the interrupt starts, check whether the value obtained by subtracting the volume compensation amount in internal register ■ from the VR attenuation amount immediately before the interrupt, that is, the volume manually preset by the user, is smaller than the DK volume (value stored in internal register I). It is determined whether or not (step S8). If small, DK
The value obtained by adding the volume and the volume compensation amount is set as the VR attenuation amount (step S9), and then gain control data from the binary encoder 30 is taken in (step 510). D
If the value obtained by subtracting the volume compensation amount from the VR attenuation amount immediately before the K interrupt is equal to or greater than the DK volume, the process directly proceeds to step 810, thereby maintaining the VR attenuation amount up to that point.

Next, it is determined whether or not there has been a change in the volume compensation amount by comparing the captured gain control data with the volume compensation amount data in the internal register ■ (step 511), and if there is a change in the volume compensation amount, ■ R attenuation is performed. Step 51: Add the amount of change in the volume compensation amount to the amount as the new VR attenuation amount.
2) Then, the volume compensation amount is updated by adding the amount of change to the value stored in the internal register (2) to obtain a new stored value (step 813). If it is determined in step Sll that there is no change in the volume compensation amount, or in step S1
After updating the sound Ω compensation amount in step 3, D from the DK decoder 16
By monitoring the K times signal detection output, it is determined whether the DK interrupt has ended or not (step 514). If the DK interrupt has not ended, the process returns to step SIO and repeats the above-described processing.

If the DK interrupt has ended, the value obtained by subtracting the volume compensation amount immediately before the interrupt from the VR attenuation amount immediately before the interrupt and the volume compensation amount updated in step S13 is set as the VR attenuation amount (step 515), and then the DK It is determined whether or not the VR attenuation amount was manually operated during the interrupt (step 516).
). If the VR attenuation amount is manipulated, the value obtained by subtracting the volume compensation amount updated in step S13 from the VR attenuation amount immediately before the end of the interrupt, in other words, the value obtained by adding the manual operation amount to the DK volume is set as the new K. It is stored in internal register I as the volume (step 517).

The process of step S17 ends or step 516
The series of processing ends when it is determined that there is no operation of the VR attenuation amount, but at the next DK interrupt, in step S8, the value obtained by subtracting the volume compensation amount from the VR attenuation amount immediately before the interruption, that is, The preset volume is DK
When g is smaller than Q, the value obtained by adding the volume compensation amount to this DK volume becomes the VR attenuation amount (step S9
), and thereafter, the value obtained by adding the volume compensation amount at each time becomes the VR attenuation amount (steps Sll to 813).

In this way, when a DK interrupt ends, the value obtained by subtracting the volume compensation rrim during the interrupt from the VR attenuation immediately before the end is stored as the DK volume (stored in the internal register), and when the DK interrupt occurs, the value is stored (stored in the internal register). By controlling the gain of the variable gain circuit 6, that is, the VR attenuation amount, so that the volume becomes the volume obtained by adding the volume compensation amount at each time to the volume value, traffic information broadcasting can be performed at approximately the same volume regardless of the driving noise. This allows you to hear the traffic information broadcast even when the driving noise is very loud, such as when driving on a cobblestone road, and prevent you from missing the traffic information broadcast even when the driving noise is low. It does not cause any discomfort to anyone.

In addition, when the electronic volume is set to the minimum and only traffic information broadcasts are received, the automatic volume adjustment process is not normally performed, and the automatic volume adjustment process is performed only when the traffic information broadcast interrupts. When receiving only traffic information broadcasts, the reproduced sounds of other sources that the user does not want to hear will not be output.

In the above embodiment, the VR attenuation amount when no volume compensation is performed and the DK volume are compared in step S8, but the VR attenuation amount immediately before the interrupt with gQ compensation and the DK volume are compared.
It is also possible to compare g and Q. A flowchart in this case is shown in FIG. In FIG. 3, the processing in steps 38a and S9a is different from the corresponding processing in FIG.
'-Et Processing in which Q is the VR attenuation amount is performed.

In addition, in the above embodiment, when a DK interrupt ends, a value obtained by subtracting the volume compensation amount during the interrupt from the VR attenuation amount immediately before the end is stored as the DK volume, and when the DK interrupt ends, the volume compensation at that time is added to the stored value. The configuration is such that the gain of the variable gain circuit 6 is controlled so that the volume becomes the sum of the volume of the DK interrupt. storage means, and subtraction means for subtracting the volume compensation amount from the volume at the end of the DK interrupt stored in these storage means, and when the DK interrupt occurs, the subtraction value by this subtraction means is added to the volume compensation amount at that time. The gain of the variable gain circuit 6 is controlled so that the volume becomes the sum of

As described in detail of the invention, in the automatic volume one stabilization device according to the present invention, at the end of receiving the traffic information broadcast, a value obtained by subtracting the volume compensation amount during reception from the volume immediately before the end is stored, When receiving a traffic information broadcast, the variable gain circuit is configured to control the volume so that the volume corresponds to the value obtained by adding the volume compensation amount to the stored value, so the traffic information broadcast can be performed regardless of driving noise. can be heard at approximately the same volume.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing a processing procedure for automatic sound adjustment executed by a processor, and FIG. 3 is a flowchart showing another processing procedure for automatic volume adjustment. It is. Explanation of symbols for main parts 1...FM tuner 6...Variable gain circuit 7...System controller 13...SDK system 7...Signal detection section noise Detection unit 30...Binary encoder

Claims (4)

[Claims] (1) An in-vehicle audio device equipped with a receiving device capable of receiving traffic information broadcasting, which has a variable gain circuit that receives an audio signal as input, and has a volume compensation amount based on the noise signal and each signal level of the audio signal. The automatic volume adjustment device adjusts the volume by determining the amount of compensation and controlling the gain of the variable gain circuit according to the amount of compensation, wherein when the reception of the traffic information broadcast ends, the volume during reception is changed from the volume immediately before the end of the traffic information broadcast. a storage means for storing a value obtained by subtracting the amount of compensation;
and control means for controlling the gain of the variable gain circuit so that when receiving the traffic information broadcast, the sound volume corresponds to an added value obtained by adding the volume compensation amount to the value stored in the storage means. Automatic volume adjustment device. (2) The automatic volume adjustment device according to claim 1, wherein the volume compensation amount is added to the stored value when the stored value is smaller than a preset volume value. (3) The automatic volume adjustment according to claim 1, wherein the addition of the volume compensation amount to the stored value is performed when the stored value is smaller than the volume value immediately before receiving the traffic information broadcast. Device. (4) An in-vehicle audio device equipped with a receiving device capable of receiving traffic information broadcasting, which has a variable gain circuit that receives an audio signal as input, and has a volume compensation amount based on the noise signal and each signal level of the audio signal. The automatic volume adjustment device adjusts the volume by determining the amount of compensation and controlling the gain of the variable gain circuit according to the amount of compensation, the device comprising: a first storage means for storing the volume at the end of reception of the traffic information broadcast; ,
a second storage means for storing the volume compensation amount during reception; a subtraction means for subtracting the volume compensation amount from the volume at the end of the reception stored in the first and second storage means; and the traffic information. and control means for controlling the gain of the variable gain circuit so that the volume corresponds to the sum of the subtracted value by the subtracting means and the volume compensation amount when broadcasting is received. Adjustment device.