JP3034876B2 - Automatic volume control device for in-vehicle audio system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic volume control device, and more particularly, to an automatic volume control device in a vehicle-mounted audio device including a receiving device capable of receiving a traffic information broadcast.

2. Description of the Related Art Traffic information, which is a so-called ARI system, in which traffic information is broadcast in a time-sharing manner during broadcast of a program of a general broadcasting station to provide services to a listener of an on-vehicle audio device such as a car radio. There is a broadcasting system.

This traffic information broadcast is performed by, for example, an FM broadcast station, but is not performed by all FM broadcast stations, but is broadcast by some specific stations. For this reason, this specific station uses a traffic information station identification signal (hereinafter, referred to as an SK signal) indicating that the station broadcasts traffic information.
It has a KHz sub-carrier and frequency-modulates this to the main carrier for transmission, so the receiver can distinguish between stations that broadcast traffic information and stations that do not broadcast based on the presence or absence of detection of this SK signal. is there.

When broadcasting traffic information, the information is generally transmitted as a monaural signal having only a main signal component.
The SK signal of z includes an area identification signal (hereinafter, referred to as a BK signal) for indicating which area the traffic information is, and an announcement identification signal (notifying that traffic information is being broadcasted) (Hereinafter referred to as a DK signal). The BK signal is one of the frequencies that are a fraction of 57 KHz (23.75 Hz to 53.98 Hz), and the DK signal is
125Hz single tone.

Announcements of traffic information are broadcast, for example, about four times an hour during a general program broadcast, at a rate of several minutes each time. On the receiver side, a DK signal of 125 Hz obtained by amplitude-modulating 57 KHz (SK signal) of the subcarrier is detected, and only when this DK signal is present, an appropriate volume can be obtained even if the volume is small. For in-vehicle audio systems that output traffic information or have other sources such as a cassette player or CD player, the DK signal is automatically detected while these players are performing. It is possible to preferentially listen to traffic information.

In an on-vehicle acoustic device having a traffic information receiving device for receiving a broadcast of such a traffic information system, traffic information is output at an appropriate volume by detecting a DK signal as described above. Since the volume is fixed to the level set by the user's operation, and the traveling noise is extremely high, such as when traveling on a cobblestone road, if the setting level is low, the output sound of the traffic information becomes the traveling noise. May be missed due to so-called masking.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic volume control device for an in-vehicle audio device that enables good reception of traffic information broadcasting regardless of running noise.

An automatic volume control device according to the present invention is an automatic volume control device in an on-vehicle audio device including a receiving device capable of receiving a traffic information broadcast, and stores a traffic information volume when sounding the traffic information broadcast. Storage means, a gain variable circuit that can adjust the gain of the audio signal, noise detection means that detects external noise to obtain a noise signal corresponding to the level of the external noise, and a volume compensation amount based on the noise signal. Means for determining, and when receiving the traffic information broadcast, when the traffic information volume stored in the storage means is higher than a set volume set in accordance with an external operation, the volume is determined with respect to the traffic information volume. Control means for controlling the gain of the variable gain circuit based on the sound volume obtained by performing sound volume compensation according to the compensation amount.

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

FIG. 1 is a block diagram showing one embodiment of the present invention.
In the drawing, an on-vehicle acoustic device according to the present invention includes an FM tuner.
1, AM tuner 2, cassette player 3, and CD player
The L and R audio outputs of one of these sources are selected by a switch circuit 5, and a gain variable circuit 6 composed of, for example, an electronic volume is provided. Through a speaker (not shown). The selection of the source by the switch circuit 5 is made by the system controller 7.

The FM tuner 1 includes a front end 9 for converting a radio wave received by the antenna 8 to an intermediate frequency (1F), a band pass filter 10 for passing the intermediate frequency from the front end 9, and a band pass filter 10 A known circuit configuration comprising an IF detection unit 11 for performing amplification detection of an intermediate frequency of the same and a noise canceling multiplex (NPX) unit 12 for reducing noise from the output of the IF detection unit 11 and performing stereo decoding. It has become.

The SDK system 13 controls the reception of traffic information based on the output of the IF detection unit 11, and includes the SK decoder 14, which identifies the SK signal, the BK signal, and the DK signal described above.
The BK decoder 15 and the DK decoder 16 are mainly configured. The SK decoder 14 detects the sub-carrier of 57 KHz, which is the SK signal, from the output of the IF detector 11 and performs detection. BK Decoder 1
5 detects the frequency of the BK signal from the output of the SK decoder 14 to identify the area. The DK decoder 16 is the SK decoder.
A DK signal of 125 Hz is detected from the output of 14, and it is determined whether or not the traffic information is being broadcast. The outputs of the decoders 14 to 16 are input to the system controller 7.

The L and R audio outputs that have passed through the gain variable circuit 6 are also supplied to a signal detector 17. The signal detecting section 17 includes an adder 18 for adding the L and R audio outputs, a gain variable circuit 19 made of, for example, an electronic volume for performing gain control on the added output of the adder 18, and a gain variable circuit. A detection / smoothing circuit 20 for detecting and smoothing the output of 19; a logarithmic compression circuit 21 for logarithmically compressing the output of the detection / smoothing circuit 20; and a logarithmic compression circuit
A time constant circuit 22 receives the output of 21 as an input. The detection output of the signal detection unit 17 becomes a subtraction input of the subtractor 23.

On the other hand, a noise detecting unit 24 for detecting noise such as a running noise of the vehicle is provided, and a detection output of the noise detecting unit 24 is a subtracted input of the subtractor 23. The noise detection unit 24 includes a microphone 25 for detecting external noise,
An amplification / filter 26 that amplifies the 25 detection output and extracts and outputs only the noise band component, a detection / smoothing circuit 27 that detects and smoothes the output of the amplification / filter 26, and a detection / smoothing circuit.
It comprises a logarithmic compression circuit 28 for logarithmically compressing the output of 27, and a time constant circuit 29 to which the output of this logarithmic compression circuit 28 is input.

The subtraction output of the subtractor 23 is supplied to a binary encoder 30 having a comparator function. Binary Enco
The comparator 30 has a comparison reference value, and the difference between the subtraction output of the subtracter 23 and the comparison reference value is used as the gain variable circuit 19
, And converts the difference into binary code digital data, which is supplied to the system controller 7 as gain control data. The variable gain circuit 19 of the signal detector 17 is provided for 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 detector 24, thereby performing stable signal detection. It is a thing.

The system controller 7 is constituted by a microcomputer, and performs various controls in accordance with a key operation command in a keyboard section 31, and controls an AM tuner 2, a cassette player 3 and a CD. Generation of a source control signal for the player 4, gain control of the variable gain circuit 6 in accordance with gain control data from the binary encoder 30, and comparison of reference values of the comparator in the binary encoder 30. Setting,
The time constant circuit 22 of the signal detection unit 17 and the time constant circuit 19 of the noise detection unit 24 are controlled to set each time constant.

Next, the procedure of the automatic volume control executed by the processor of the system controller 7 will be described with reference to the flowchart of FIG.

The processor first stores a value preset at the time of shipment as a volume at the time of receiving a traffic information broadcast (hereinafter referred to as DK volume) in an internal register I, and further stores an initial value 0 as a volume compensation amount at the time of automatic volume adjustment. The gain control data is stored in the register II (step S1), and the gain control data from the binary encoder 30 is fetched (step S2). Then, it is determined whether or not the volume compensation amount has changed by comparing with the data (the initial value is 0) (step S3). If there is a change in the volume compensation amount, it is determined whether the attenuation amount (hereinafter, referred to as VR attenuation amount) in the gain variable circuit 6 is-、, that is, whether the electronic volume is the minimum (step S4), and -∞. If not, a new VR attenuation amount is obtained by adding the change amount of the volume compensation amount to the attenuation amount (step S5), and the change amount is updated by storing the change amount in the internal register II. (Step S6).

If it is determined that there is no change in the volume compensation amount in step S3, or after the volume compensation amount is updated in step S6, the SDK
By monitoring the detection output of the DK signal from the DK decoder 16 in the system 13, it is determined whether or not the interruption of the traffic information broadcast (hereinafter referred to as DK interruption) is started (step
S7) If the interrupt has not started, the process returns to step S2 to repeat the above-described processing. If the interrupt is started,
The value obtained by subtracting the volume compensation amount of the internal register II from the VR attenuation amount,
That is, it is determined whether or not the volume manually set in advance by the user is lower than the DK volume (the value stored in the internal register I) (step S8). If it is small, the value obtained by adding the DK sound volume and the sound volume compensation amount is set as the VR attenuation amount (step S9), and thereafter, the gain control data from the binary encoder 30 is fetched (step S10). If the value obtained by subtracting the sound volume compensation amount from the VR attenuation amount immediately before the DK interrupt is equal to or higher than the DK sound volume, the process directly proceeds to step S10 to maintain the previous VR attenuation amount as it is.

Subsequently, the acquired gain control data is stored in the internal register II.
It is determined whether or not the volume compensation amount has changed by comparing with the volume compensation amount data (step S11). If the volume compensation amount has changed, the change amount of the volume compensation amount is added to the VR attenuation amount. The new volume is used as a new VR attenuation amount (step S12), and the change is added to the value stored in the internal register II to obtain a new stored value, thereby updating the volume compensation amount (step S13). If it is determined in step S11 that there is no change in the volume compensation amount, or after updating the volume compensation amount in step S13, the DK interrupt is terminated by monitoring the detection output of the DK signal from the DK decoder 16. Is determined (step S14), and if the DK interrupt is not completed, the process returns to step S10 to repeat the above processing.

If the DK interrupt is completed, the value obtained by adding the volume compensation amount updated in step S13 to the value obtained by subtracting the volume compensation amount immediately before the interrupt from the VR attenuation amount immediately before the interrupt is used as the VR attenuation amount (step
S15) Then, it is determined whether or not the VR attenuation amount has been manually operated during the DK interruption (step S16). When the VR attenuation amount is operated, 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, and the value obtained by adding the manual operation amount to the internal register I as the new DK volume.
(Step S17).

When the processing in step S17 is completed or in step S16 VR
When it is determined that there is no operation of the attenuation amount, a series of processing ends.In the next DK interrupt, a value obtained by subtracting the volume compensation amount from the VR attenuation amount immediately before the interrupt in step S8, that is, a preset value When the obtained volume is lower than the DK volume, the value obtained by adding the volume compensation amount to the DK volume becomes the VR attenuation amount (step S9), and the value obtained by adding the volume compensation amount at that time becomes the VR attenuation amount (step S9). Steps S11 to S13).

As described above, when the VR attenuation amount is manually operated during the DK interrupt, the value obtained by subtracting the volume compensation amount during the interrupt from the VR attenuation amount immediately before the end of the DK interrupt is stored as the DK volume at the end of the DK interrupt. If the preset volume is lower than the DK volume, the gain variable circuit 6 is controlled to add the volume compensation amount at that time to the stored (stored) value at the time of the DK interrupt. By controlling the gain, that is, the amount of VR attenuation, the traffic information broadcast can be heard at almost the same volume in terms of audibility regardless of the running noise.
Even if the driving noise is very loud, such as when driving on a cobblestone road, the traffic information broadcast will not be overlooked, and if the driving noise is low, the output sound of the traffic information will be too loud and cause discomfort to the listener Not at all.

When the electronic volume receives the minimum traffic information broadcast only, the automatic volume adjustment process is not normally performed, and the automatic volume adjustment process is performed only when the traffic information broadcast is interrupted. Therefore, when only the traffic information broadcast is received, the reproduced sound of another source which is not desired to be heard is not output.

In the above-described embodiment, the VR attenuation and the DK volume when the volume compensation is not performed in step S8 are compared. However, the VR attenuation and the DK volume immediately before the interrupt in which the volume compensation is performed may be compared. It is possible. FIG. 3 shows a flowchart in this case. In FIG. 3, the processing in steps S8a and S9a is different from the corresponding processing in FIG.
In S8a, a comparison between the VR attenuation amount immediately before the interruption and the DK sound volume is performed, and in step S9a, a process of setting the DK sound volume to the VR attenuation amount is performed.

Further, in the above embodiment, when the VR attenuation amount is manually operated during the DK interrupt, the value obtained by subtracting the volume compensation amount during the interrupt from the VR attenuation amount immediately before the end of the DK interrupt is used as the DK volume. Remember, the preset volume is DK
When the volume is lower than the volume, the gain of the variable gain circuit 6 is controlled so that the volume is obtained by adding the volume compensation amount at that time to the stored value at the time of the DK interrupt. However, the present invention is not limited to this. First storage means for storing the volume at the end of the DK interrupt, second storage means for storing the volume compensation amount during the interruption, and DK stored in these storage means. A subtraction means for subtracting the volume compensation amount from the volume at the end of the interruption is provided. At the time of the DK interruption, the system controller 7 uses the volume obtained by adding the volume compensation amount at each time to the subtraction value of the subtraction means, and the system controller 7 May be controlled.

Effect of the Invention As described above, in the automatic volume control device according to the present invention, in the automatic volume control device in the vehicle-mounted audio device according to the present invention, first, the traffic information volume at the time of outputting the traffic information broadcast is stored. In addition, an external noise is detected, and a volume compensation amount is obtained based on the external noise. Here, when the traffic information broadcast is received, if the traffic information volume is higher than the volume set by the user at that time, the traffic information volume is determined according to the volume compensation amount. The sound volume is adjusted based on the sound volume obtained by performing the sound volume compensation. Therefore, even if the noise during traveling is high, the sound volume is automatically adjusted so that the traffic information broadcast can be heard well.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a flowchart showing a processing procedure of automatic volume adjustment executed by a processor, and FIG. 3 is another processing procedure of automatic volume adjustment. FIG. Description of Signs of Main Parts 1 FM Tuner 6 Gain Variable Circuit 7 System Controller 13 SDK System 17 Signal Detector 24 Noise Detector 30 Binary Encoder

Claims (8)

(57) [Claims] 1. An automatic volume control device in an on-vehicle audio device including a receiving device capable of receiving a traffic information broadcast, comprising: storage means for storing a traffic information volume when the traffic information broadcast is acoustically output; A gain variable circuit that can adjust the gain of the audio signal; a noise detection unit that detects external noise to obtain a noise signal corresponding to the level of the external noise; and a unit that obtains a volume compensation amount based on the noise signal. When receiving the traffic information broadcast, when the traffic information volume stored in the storage unit is higher than a set volume set in accordance with an external operation, the traffic information volume depends on the volume compensation amount. Control means for controlling the gain of the gain variable circuit based on the sound volume obtained by performing the sound volume compensation. 2. An automatic volume control device in an on-vehicle audio device including a receiving device capable of receiving a traffic information broadcast, wherein the storage device stores a traffic information volume when the traffic information broadcast is acoustically output; A variable gain circuit that can adjust the gain of an audio signal; a noise detection unit that detects external noise to obtain a noise signal corresponding to the level of the external noise; an audio signal and the noise signal output from the variable gain circuit Means for obtaining a volume compensation amount based on the above, and when the traffic information volume stored in the storage means at the time of receiving the traffic information broadcast is higher than a set volume set according to an external operation, Control means for controlling the gain of the variable gain circuit based on the volume obtained by performing volume compensation on the traffic information volume in accordance with the volume compensation amount. Automatic volume adjusting apparatus in the vehicle audio apparatus according to. 3. An automatic volume control device in an on-vehicle audio device including a receiving device capable of receiving a traffic information broadcast, wherein the storage device stores a traffic information volume when the traffic information broadcast is output as sound. A gain variable circuit that can adjust the gain of the audio signal; a noise detection unit that detects external noise to obtain a noise signal corresponding to the level of the external noise; and a unit that obtains a volume compensation amount based on the noise signal. When the traffic information volume stored in the storage unit at the time of receiving the traffic information broadcast is higher than the volume immediately before the reception of the traffic information broadcast, the traffic information volume is based on the volume compensation amount. Control means for controlling a gain of the gain variable circuit based on a sound volume obtained by performing sound volume compensation. 4. An automatic sound volume control device in an on-vehicle audio device including a receiving device capable of receiving a traffic information broadcast, wherein: a storage means for storing a traffic information sound volume when sound output of the traffic information broadcast is provided; A variable gain circuit that can adjust the gain of an audio signal; noise detection means that detects external noise to obtain a noise signal corresponding to the level of the external noise; an audio signal and the noise signal output from the variable gain circuit Means for determining a volume compensation amount based on the traffic information, and when the traffic information volume stored in the storage means at the time of receiving the traffic information broadcast is higher than the volume immediately before receiving the traffic information broadcast, the traffic Control means for controlling the gain of the gain variable circuit based on the volume obtained by performing volume compensation in accordance with the transmission volume compensation amount for the information volume. Automatic volume adjusting apparatus in the vehicle audio apparatus according to. 5. An automatic volume control device in an on-vehicle audio device including a receiving device capable of receiving a traffic information broadcast, wherein: a storage means for storing a traffic information volume when the traffic information broadcast is acoustically output; A gain variable circuit that can adjust the gain of the audio signal; and, when an external operation for adjusting the gain of the gain variable circuit is performed during reception of the traffic information broadcast, the traffic according to the adjustment value by the external operation. An automatic sound volume control device for an on-vehicle audio device, comprising: a traffic information sound volume updating unit for updating an information sound volume. 6. An automatic volume control device in an on-vehicle audio device including a receiving device capable of receiving a traffic information broadcast, wherein: a storage means for storing a traffic information volume when the traffic information broadcast is acoustically output; A gain variable circuit capable of adjusting the gain of an audio visit, and maintaining the traffic information volume until an external operation for adjusting the gain of the gain variable circuit is performed during reception of the traffic information broadcast. Automatic volume control device for in-vehicle audio equipment. 7. A traffic information volume, further comprising: noise detection means for detecting an external noise to obtain a noise signal corresponding to the level of the external noise; and means for obtaining a volume compensation amount based on the noise signal. The updating unit, after the reception of the traffic information broadcast is completed, sets a volume obtained by removing the volume of the volume compensation amount from the traffic information volume stored in the storage unit as the new traffic information volume in the storage unit. 6. The automatic volume control device for an on-vehicle acoustic device according to claim 5, wherein the traffic information volume is updated after being stored. 8. A noise detecting means for detecting an external noise to obtain a noise signal corresponding to the level of the external noise, and a sound volume based on a signal level of the audio signal output from the gain variable circuit and the noise signal. Means for calculating a compensation amount, wherein the traffic information volume updating means calculates the amount of the volume compensation amount from the traffic information volume stored in the storage means after the reception of the traffic information broadcast ends. 6. The automatic volume control device according to claim 5, wherein the removed volume is stored as a new traffic information volume in the storage unit, and the traffic information volume is updated.