JPH0229016A - Equalizer - Google Patents

Abstract

PURPOSE:To facilitate the preset operation and to improve the sense of high- class external appearance by presetting the equalizer characteristic at application of power with a control data at poweroff and applying the said present with a standard control data if the control data is in error. CONSTITUTION:The state of preset keys 25g-25k just before power is interrupted is stored in a prescribed memory area of a RAM 23. Moreover, other ROM is provided to a ROM 22 of a microcomputer 20 and a standard preset data is stored. Then a control data stored in the RAM 23 is checked at application of power. If the data is a meaningless data, the standard control data stored in the ROM is read and written in the preset memory area of the RAM 23. Thus, the equalizer characteristic is always kept to a prescribed state and the reproduction of an abnormal sound is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a graphic equalizer suitable for in-vehicle audio equipment such as car stereos.

In-vehicle audio equipment that integrates an AM/FM radio, tape recorder, etc. is known as a so-called car stereo, and has become almost an indispensable equipment in the modern automobile civilization.

In addition, the demand for Hi-Fl audio equipment extends to car stereos, and as devices with superior acoustic characteristics come into use, it is becoming more and more important to correct the acoustic characteristics in automobiles and adjust the frequency characteristics by programming. Correction also requires careful consideration, which is why car stereos are now equipped with graphic equalizers.

This graphic equalizer (hereinafter referred to as GEQ) divides the frequency band of an audio signal into a number of frequency bands, or channels, and changes the level characteristics for each channel so that the frequency characteristics over all bands can be changed arbitrarily. In terms of -a, there are many combinations of simulated inductors and bridge amplifiers using operational amplifiers (this is what is used, and this GE
By providing a Q in a car stereo, the above requirements can be met.

By the way, this GEQ is equipped with a large number of variable resistors or switches for adjustment, corresponding to the channels mentioned above, so operating them requires considerable skill, and even then, it is quite troublesome and troublesome. It has been manipulated.

Therefore, when changing the program, it is not a great psychological burden for the user to repeatedly operate the GEQ according to the change. However, there was a risk that it would turn out to be extremely undesirable.

Therefore, in order to solve this problem, it is necessary to set data corresponding to the various frequency characteristics to be obtained by GEQ in advance in memory, etc., and select one of the preset data when necessary. A so-called presettable GEQ is known, which can provide arbitrary frequency characteristics with just one input.

This presettable GEQ (hereinafter referred to as PGEQ)
According to , it can be installed in car stereos, etc., and can be easily and safely operated to provide the necessary equalization characteristics, so the functions of audio equipment equipped with GEQ can be fully demonstrated, and car stereos, etc. It is possible to sufficiently improve the performance and luxury of.

However, on the other hand, in such conventional PGEQ, the equalization characteristics are given by the control data read from the memory. It is not possible to know what the frequency characteristics are.

Therefore, a PC is equipped with a display device capable of two-dimensional display, and the control data supplied to the signal transmission circuit is manually input to this display device so that it can be recognized by displaying characteristic curves on a plane; EQ has been proposed, and according to this, it is possible to immediately recognize what kind of frequency characteristics are currently given to the audio signal, regardless of the position of the operation keys on the operation panel. You can further enhance the sense of luxury.

By the way, if the equalization characteristics are preset using control data stored in such a memory means, the control data will be lost each time the power is turned off, and the preset operation will have to be performed each time the power is turned on. This poses a problem in that the operations have to be repeated, the operations are complicated, and the sense of luxury is significantly impaired.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to eliminate the need for extra operations even when the power is turned on, and to eliminate particularly unpleasant equalization characteristics. PG that allows comfortable movement changes
The purpose is to provide EQ.

To achieve this objective, the present invention provides that whenever the power is turned on, the equalization characteristics that were set when the power was last turned off are automatically preset, and The feature is that when there is an abnormality in the control data, standard equalization characteristics are automatically preset.

Embodiments of the equalizer device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment in which the present invention is realized by microcomputer control, in which 1 is a GEQ section, 2 is a control section, and 3 is a level detection section.

In the GEQ section 1, 10.11 is the R channel and L channel audio signal input terminal, 12 is the bridge amplifier, 13 is the analog switch, 14 is the simulated inductor, 15 is the mute circuit, and 16.17 is the R channel and L channel. This is the audio signal output terminal for the channel.

In the control unit 2, 20 is a microcomputer, 21 is a central processor unit (CPU), 22 is a read-only memory (ROM) for storing programs, 23
is the random access memory (RAM), 24 is the input/output bag W ([,10), 25 is the switch part of the PGEQ operation panel, 26 is the display part of the operation panel,
27 is a data latch.

Note that the level key output unit 3 will be described later.

Next, the operation will be explained.

The bridge amplifier 12 constitutes a signal transmission circuit for G F and Q, has independent signal transmission circuits for R channel and L channel signals, and has an analog switch 1.
3 to the simulated inductor 14, which divides the entire band of the audio signal into a number of frequency channels, e.g.
The amount of signal passing through each channel is controlled according to the switching state of No. 3, so that an arbitrary frequency characteristic can be provided.

The mute circuit 15 is provided to eliminate transient changes in the audio signal output that occur when the analog switch 13 is switched and the equalization characteristic provided by the bridge amplifier 12 changes in a stepwise manner.

Therefore, the audio signals supplied from the input terminals 10, 11 are subjected to predetermined equalization processing according to the switching state of the analog switch 13, and are supplied to the output terminals 16, 17, thereby operating as a GHQ.

Next, the operation of supplying control data A to the analog switch 13 will be explained.

The switch section 25 of the operation panel is configured as shown in FIG. 2, for example, and 25a to 25e are slide encoders;
5f is a memory key, 25g to 25 are preset keys, and 251 is an f special/level key.

The slide encoders 25a to 25e are used to adjust the amount of attenuation or gain for each of the five frequency channels, and are designed to generate nine types of control data using 4 bits depending on the slide position. The control data is designed to correspond to the output level.

Memory key 25f is slide encoder 25a-25
This switch is used when storing control data representing the output level for each frequency channel set by e at a predetermined address in the RAM 23 of the microcomputer 20. The data to be stored at this time requires an output level of 4 bits for each of the 5 channels, resulting in a total of 20 bits.

Addresses in the RAM 23 are designated to the preset keys 25g to 25, and control data is read from those addresses, and when the memory key 25f is pressed, the corresponding address in the RAM 23 is set by the slide encoders 25a to 25θ. It functions to write control data.

The f special/level key 251 is used to switch display contents, and will be described in detail later. In addition, these keys 25f~2
51 are all of the so-called touch switch type.

The display unit 26 includes a matrix display 26a shown in FIG. 2 and indicator lights 26f provided in each of the keys 25f to 25N.
~26β, of which the matrix display 26
A is a display capable of two-dimensional display in which (5×9) dot-shaped display elements 26a(1) are arranged in a matrix.

The data latch 27 holds the data written via the l1024 of the microcomputer 20, and transfers it to the analog switch 1.
3 and the mute circuit 13.

The RAM 23 of the microcomputer 20 is provided with the following four types of memory areas.

(1) Current data memory Memory that stores the control data output from the slide encoders 25a to 25e according to their current operating positions. (2) Output data memory Stores the control data currently output to the data latch. Memory for storing (3) Preset memory Memory for storing five types of independent control data corresponding to preset keys 25g to 25k (4) Display output memory - Matrix display 26a and respective indicator lights 26f to 2
If the slide encoders 25a to 25e are operated now, the contents of the current data memory will be rewritten accordingly.
At this time, memory key 25f, preset key 25g
25, the contents of this current data memory are given as they are to the output data memory.

As a result, these slide encoders 25a to 25e
The control data from them is directly applied to the analog switch 13 via the data latch 27 in response to the operation of the audio signal.
Can be controlled arbitrarily.

Also, at this time, the contents of the output data memory are given to the display output memory, so that the display element 26a(1) of the display 26a displays the attenuation ff1 (or gain) for each frequency channel, as shown in FIG. ), one display element lights up to display the currently given frequency characteristics.

Next, when the memory key 25f is pressed in this state, the indicator light 26f lights up for about 5 seconds, indicating that memory is possible.

Therefore, when any one of the preset keys 25g to 25 is subsequently pressed, one of the indicator lights 26g to 26 for that pressed key lights up, and the current information is stored in the corresponding preset memory. The contents of memory are written. At the same time, the indicator light 2 of the memory key 25r
6f disappears, indicating that the memory is no longer available. Note that if one of the preset keys 25g to 25k is not pressed within 5 seconds after pressing the memory key 25f, the indicator light 26f will remain turned off. In addition, the indicator lights 2 for these preset keys 25g to 25
For 6g to 26, two or more preset keys do not light up at the same time, and when two or more preset keys 25g to 25k are pressed at the same time, only the indicator light of the last key pressed among them lights up. .

In this way, when one of the preset keys 25g to 25 is pressed and one of the corresponding indicator lights 26g to 26 lights up, the contents of the preset memory corresponding to that key are read out and output data is stored. Therefore, at this time, the analog switch 13 is controlled by the control data written in this preset memory, and an equalization characteristic corresponding to the control data is given to the audio signal.

At the same time, the contents of the display output memory are also rewritten with the contents of the output data memory, so at this time the equalization characteristics given to the preset keys 25g to 25 are displayed on the display 26a.

On the other hand, when the indicator light 26f of the memory key 25f is not lit, that is, when this key is not pressed, or when one of the preset keys 25g to 25 is pressed after 5 seconds or more have elapsed since the key was pressed, the slide encoder 25a to
25e, that is, regardless of the current contents of the data memory, the contents of the corresponding preset memory are given as they are to the output data memory, and at this time, the control data stored in advance, that is, the preset data, controls the analog switch 13. is controlled, a corresponding equalization characteristic is given, and
This will be displayed on the display 26a. As already explained, writing of these preset data can be done by operating the slide encoders 25a to 25e, the memory key 25f1, and the corresponding preset keys 25g to 25.

Also, when the indicator lights 26g to 26k of any one of the preset keys 25g to 25 are lit, that is, when the equalization characteristic is set by the preset data, one of the slide encoders 25a to 25e If even one of them is operated, the control state based on the preset data is reset, the contents of the current data memory are written to the output data memory, and adjustments are made to give an arbitrary frequency characteristic using the slide encoders 25a to 25e. You will be able to do that.

The above operations are all performed by a program written in the ROM of the microcomputer 20, and the CPU 21 of the microcomputer 20 is connected to the switch section 251, display section 26, and data latch 27 via l1024. Input data is taken in and sent out according to a predetermined procedure, and data is written to and read from the RAM 23 to perform necessary processing.

Therefore, according to this embodiment, the frequency characteristics by the GEQ installed in a car stereo etc. can be determined by the slide encoder 25.
A to 25e can be arbitrarily adjusted, and five types of preset equalization characteristics can be arbitrarily selected by one-touch operation of preset keys 25f to 25. Since the frequency characteristics given to the audio signal are displayed on the matrix display 26a as shown in FIG. 3, the operating state can be fully grasped at all times.

Incidentally, in the embodiment described above, the level detection section 3 is provided, so that the level of the output audio signal can be independently displayed for each channel of the GEQ by the matrix display 26a.

Therefore, this point will be explained below.

In FIG. 1, 30 is an adder circuit, 31 is a bridge amplifier, 32 is an analog switch, 33 is a simulated inductor, and 34 is an analog-to-digital converter (A/D converter).
D).

The adder circuit 30 receives R obtained from the output of the bridge amplifier 12.
The audio signals of the channel and the L channel are combined into one channel signal, and the signal is supplied to the input of the bridge amplifier 31.

Bridge amplifier 31. The analog switch 32° simulated inductor 33 is connected to the bridge amplifier 12, respectively.
．． Analog switch 13. It may be the same as the simulated inductor 14, and when the analog switch 32 is controlled by the control data B from the data latch 27 of the control unit 2, five types of bandpass filters whose passband is the frequency band of each channel of GEQ are created. As shown in Figure 4,
The contact 32 of the analog switch 32 is controlled by the control data B.
a is sequentially and periodically switched, and each of the inductors 33a to 33e of the simulated inductor 33 is selectively switched and connected to the bridge amplifier 31. As a result, the inductors 33a to 33e of the simulated inductor 33 are connected to the bridge amplifier 31. When the audio signal IN is turned on, only the signal of mainly the 60Hz component of the audio signal IN is taken out to the output LA, and the inductor 3
When 3b is connected, the main component is 250 Hz, and inductor 33c has a 1 kHz component, inductor 33d has a 3.5 kHz component, and inductor 33e has a 3.5 kHz component.
In this case, 10 kHz is respectively taken out to the output LA.

Therefore, an analog signal representing the level of each channel of the audio signal from the adder circuit 3o appears repeatedly and periodically on the output LA.

The A/D 34 receives the analog signal of the output LA and converts it into 4-bit digital level data L.

Therefore, if you press the f special/level key 25β provided on the switch section 25 of the operation panel, this key 25
The signal from 1 is read by the microcomputer 20 via l1024, and first, the contents corresponding to the indicator light 26β in the display memory are rewritten, the indicator light 261 lights up, and the display 26
This indicates that the display mode of a has changed from the previous frequency characteristic display mode (the display mode shown in FIG. 3) to the level display mode. At the same time, the display operation program is switched by input from the f special/level key 25N, and the microcomputer 20 sends control data B to the analog switch 32 via the data latch 27, and sequentially outputs the audio signals of each channel to the A/ D34, and the resulting digital level data Lo is written into the display output data memory of the RAM23.

As a result, the display elements 26a(1) corresponding to each channel of the matrix display 26a light up sequentially from the bottom in a bar graph shape, the number of which corresponds to the level of the audio signal of that channel, and each channel is illuminated as shown in FIG. It works so that each level is displayed in a dynamic state.

Therefore, according to this embodiment, by operating the f/level key 251 as necessary, the output level of each frequency band of the audio signal can be displayed, and the operating status of a car stereo etc. can be displayed in many ways. It is possible to understand the situation and provide an excellent usability.

In addition, in the above embodiment, this f special/level key 2
If you press 5N first, the indicator light 26ffi lights up and you enter the level display mode, and if you press it next while the indicator light 26j2 is lit, this indicator light 261 goes out and you switch to the frequency characteristic display mode. There is, but memory key 2
When pressing 5f or any of the preset keys 25g to 25, the mode will automatically change to the frequency characteristic display mode for about 5 seconds, and during that time input from the f special/level key 25N will not be accepted. You may also do so.

According to this, when writing new control data to the preset memory and when setting the GEQ equalization characteristics using the preset control data, the frequency characteristics can be visually checked, and incorrect characteristics can be detected. can be prevented from being given.

By the way, it goes without saying that equipment using such a microcomputer requires initialization to start the program operation from a predetermined operation every time the power is turned on. If it is random, preset key 25g~25k
The equalization characteristics given when you press the button are random, and unpleasant sounds may be played from your car stereo when you turn on the power switch.

Furthermore, if the preset data disappears every time the power is turned off, the memory operation must be repeated each time, which is cumbersome.

Therefore, in the above embodiment, the RAM 23 is provided with a power backup system such as a battery so that the data in the RAM 23 is saved regardless of whether the car stereo or other power source is turned on or off. Next time you turn it on, the preset key will also be 25g~25.
When k is pressed, preset data is immediately given, and necessary equalization characteristics can be given with one touch while checking on the display 26a.

Further, in the above embodiment, the ta backup method of the RAM 23 is used to store the states of the preset keys 25g to 25 immediately before the power is turned off in a predetermined memory area of the RAM 23, and the next time the power switch is turned on, the states of the preset keys 25g to 25 are stored. The program determines the contents of a predetermined memory area of this RAM 23 during the initialization operation when the power is turned on, so that the operating state of the PGEQ at the first time after the power is turned on is the same as the state when the power is turned off. It is.

As a result, when the previous state when the power source was turned off was the state in which the GEQ equalization characteristics were given by the slide encoders 25a to 25e, that is, the contents of the current data memory were being read to the output data memory. ,Next, when the power supply 1 is turned on, the operation will start in that state, and when the tS switch is turned off, any one of the indicator lights of preset keys 25g to 25 will be lit, and If the equalization characteristics are given according to the contents of the corresponding preset memory, the indicator light for that preset key will light up the next time the power is turned on, and the equalization characteristics will be given according to the contents of the corresponding preset memory. As a result, the operation becomes extremely easy and the high-class atmosphere of the device can be sufficiently enhanced.

Furthermore, in the above embodiment, the ROM2 of the microcomputer 20
2 or a separate ROM, store standard preset data in it, and check the control data stored in the preset memory area of RAM 23 during the initialization operation program when the power is turned on. , when the data becomes meaningless,
A program is added that reads the standard control data stored in the ROM and writes it to the preset memory area of the RAM 23.According to this program, the user must switch 1 to the power switch for the first time after shipping from the factory. The equalization characteristics are always kept in the specified state in both cases, when the control data stored in the preset memory area of the RAM 23 is destroyed when the power is turned on due to some reason such as a failure of the backup power supply. It is possible to prevent abnormal audio from being played.

Next, the audio signal input to such PGEQ is supplied from the tape deck of the car stereo, and then
Usually, it is also supplied from an M-AM tuner.

Therefore, as an embodiment of the present invention, the display mode of the matrix display 26a of the display section 26 is switched not only to the above-mentioned frequency characteristic display mode and level display mode, but also to a tape deck operation display mode and a tuner operation display mode. You may also do so.

FIG. 6 shows an example of this, where 40 is a tape deck, 41 is a tuner, and 42.43 is an analog-to-digital converter (
A/D), and the rest is the same as the embodiment shown in FIG.

Various data representing the operating state or operating state of the tape deck 40, such as volume (VOL), balance (BA
L), sound f (BASS, THE), fader (FA
The data D such as DER) is left as is, and the signal level LRL is sent to the microcomputer 20 via the A/D 42.
of! 1024.

The same goes for the tuner 41, the data T representing the tuning frequency remains unchanged, and the signal level L is changed from the A/D.
43 to the microcomputer 20.

FIG. 7 shows an embodiment of the switch section 25 and the display section 26. The switch section 25 is provided with a deck display key 25m and a tuner display key 25n in addition to the f special/level key 251, while the display section 26 is provided with a deck display key 25m and a tuner display key 25n. , M) IJ indicator 26a
is formed of a two-dimensional display section having 8×9 display elements 26a(1), and further includes indicator lights 26 for keys 25m and 25n.
m, 26n, and an illumination part for identifying display contents, and this proof part is an EQ display part 26a (2),
It has a deck display section 26a(3), a tuner display section 26a(4), and further includes tuner tuning frequency display sections 26a(5) and 26a(6).

Therefore, when the deck display key 25m is pressed now, it is read by the program of the microcomputer 20 and the program for the display section 26 is switched to the deck display, so the indicator light 26m lights up and at the same time the deck display section 26a (3 ) is illuminated. In addition, keys 25m and 25n
When none of these are pressed, the EQ display area 26
a (2) is illuminated.

At this time, as shown in FIG.
VOL, BAL, BASS, TRE depending on the operating status of
etc. are displayed according to the vertical lighting position of the display element 26a(1), and at the same time, the levels L and R of the left channel and right channel signals are displayed in the form of a bar graph.

Further, when the tuner display key 25n is pressed, the indicator light 26n lights up and the tuner display section 26a
(4) is illuminated, and furthermore, depending on the operating state of the tuner 41, the tuned frequency display section 26a is displayed as shown in FIG.
(5), 26a(6) is illuminated, and one display element 26a(1) whose tuning frequency is in the horizontal direction
The level of the received signal is displayed in the form of a horizontal bar graph.

Note that when the f special/level key 25N is pressed, the EQ display section 26a (2) is illuminated, and at this time, the GHQ equalization characteristic and the level display are switched alternately each time the key 251 is pressed. This is the same as in the embodiment shown in FIG.

Therefore, according to this embodiment, in a car stereo equipped with a tuner, etc., all the operating conditions and operating conditions thereof can be known from the display section 26, and the operation can be performed easily and always accurately.

In the above embodiment, the control data for GEQ is set using the slide encoders 25a to 25e, but instead of this, it is possible to use an encoder that is automatically operated by up and down keys. You may also do so.

Further, as the matrix display 26a, any one such as a light emitting diode, liquid crystal, or fluorescent display tube may be used, and if necessary, a cathode ray tube or the like may be used.

As explained above, according to the present invention, even in the PGEQ, which uses control data preset in memory and allows the necessary equalization characteristics to be set with a single touch, when the power is turned on, the equalization characteristics are always accurate even when the power is turned on. Since the settings can be made reliably, the drawbacks of the prior art can be eliminated, and accurate operation can be performed at all times, making it possible to provide a high-class car stereo equipped with a high-class PGEQ that is easy to use.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the equalizer device according to the present invention, FIG. 2 is a front view showing an example of the operation panel thereof, FIG. 3 is an explanatory diagram showing the frequency characteristic display mode, and FIG.
FIG. 5 is a block diagram showing an example of a level detection section, FIG. 5 is an explanatory diagram showing a level display mode, FIG. 6 is a block diagram showing another embodiment of the present invention, and FIG. 7 is an example of the display section. The front view, FIGS. 8 and 9 are explanatory diagrams showing display modes. 1...Graphic equalizer section, 2.
......Control section, 3... Level detection section. Koi Z 73 No. 4F211 5th year 6th year ε times

Claims (1)

[Claims] A signal transmission circuit whose frequency characteristics over almost the entire audio signal frequency band can be controlled by electrical control data, a memory means capable of writing and reading the control data, and a memory means capable of generating the control data. In the graphic equalizer device, the graphic equalizer device is equipped with an operation input means for controlling the writing and reading of control data to and capable of presetting an equalization characteristic, and a control data storage means for saving the contents of the memory means when the power is turned off; fixed memory means for holding predetermined standard control data independently of the control data generated from the operation input means; and control data determination means for checking the control data read from the memory means when the power is turned on. When the power is turned on, the equalization characteristics are preset using the control data stored in the memory means, and when it is determined that there is an abnormality in the control data read from the memory means, the equalization characteristics are preset using the control data stored in the memory means. An equalizer device characterized in that it is configured to preset equalization characteristics using standard control data.