JPH077027B2 - Frequency component display device - Google Patents

Description

The present invention relates to a frequency component display device of the present invention, and more particularly to a frequency component display device of a signal suitable for use in a spectrum analyzer display of an audio signal.

<Prior Art> Audio equipment is equipped with a spectrum analyzer display (spectrana display) to directly display the signal level in each frequency band, and the signal level in each frequency band is displayed in real time. It is designed to be displayed in a graph. Therefore, the listener can recognize the level of the low frequency band, the high frequency band, or the middle frequency band at a glance of the spectrum analyzer display, and can easily determine whether or not each band has a desired level characteristic. it can. FIG. 9 is an external view of a conventional spectrum analyzer display.
A frequency axis x having a frequency scale of 0, 120, 250, ... (Hz) is assigned to a signal level axis y from MIN to MAX in the upward direction. The frequency scale indicates the center frequency of the band. And, for each frequency band, a plurality (for example,
Display elements rows 20-1, 20-2, ..., 20-n are formed by arranging 13 display elements 10a in a line in the signal level axis direction.

According to this spectrum analyzer, the lower display element is lit when the signal level is low for each frequency band, and the upper display element is lit as the signal level increases.

<Problems to be Solved by the Invention> In such a conventional spectrum analyzer, all the display elements from the lowest level to the signal level are lit with the same brightness for each frequency band, and the temporal change of the audio signal is caused. When the level changes, when the level increases, from the MIN side to the MAX
The number of lit display elements only increased to the side, and conversely when the level decreased, the number of lit display elements decreased from the MAX side to the MIN side.

Therefore, the conventional spectrum display has a problem that it is visually unattractive due to repeated monotonous movements and is difficult to see.

From the above, it is an object of the present invention to provide a frequency band display device that is attractive, easy to see, and enjoyable to see.

<Means for Solving the Problems> FIG. 1 is a block diagram of a spectrum analyzer display device according to the present invention.

Reference numeral 1 is a level detector, 2 is a control microcomputer having a brightness control means 2b, and 3 is a display unit.

<Operation> The display unit 3 is configured by arranging the display element rows for level display corresponding to each frequency band, and the level detection unit 1 detects the audio signal level in each frequency band at predetermined time intervals and controls it. The brightness control means 2b of the microcomputer 2 turns on all display elements from the lowest level to the detection level for each frequency band, and decreases the brightness of the display elements from the detection level to the lowest level. As a result, the spectrum display is performed as if the upper limit display elements were moving while leaving afterglow.

<Embodiment> FIG. 1 is a block diagram of a spectrum analyzer display device according to the present invention.

Reference numeral 1 is a level detecting section for detecting an audio signal level in each frequency band, 2 is a control microcomputer having a brightness control means, timing control means, etc., 3 is a display unit in which display element rows are arranged corresponding to each frequency band,
Reference numeral 4 is an equalizer section for controlling the frequency characteristic of the audio signal AS, 5 is an operation section equipped with various keys, 6 is a digit driver, and 7 is a segment driver, which drive each display element of the display unit 3. And display the spectrum analyzer.

The level detector 1 sets the frequency band of the audio signal to N
(For example, N = 14) When divided, a filter unit 1a having a bandpass filter BPFi (i = 0,2, ..., 9, A, B, C, D) for each frequency band, and A frequency time division circuit 1b that selects an output Li (i = 0 to D) of a predetermined bandpass filter BPFi and an input signal level L is compared with a reference level to determine which of M steps (for example, M = 13). It has a level comparator 1c for discriminating whether or not.

Control microcomputer 2 is a bandpass filter output Li
(I = 0 to D) switching signal BCS, timing control function 2a for controlling the timing of outputting segment drive signals S _{o to} S _c and digit drive signals D _{o to} D _D, which will be described later, the lowest level for each frequency band Brightness control means 2b for turning on all the display elements from the level to the detection level and decreasing the brightness of the corresponding display elements from the detection level to the lowest level
And equalizer control means 2c and the like.

As shown in FIG. 2, the display unit 3 has a frequency axis x having a frequency scale of 60, 120, 250, ... (Hz) to the right of the display panel surface 3a, and a signal level axis y from MIN to MAX in the upward direction. It is assigned. Then, a plurality of (for example, 13) display elements 3b for each frequency band are arranged in a line toward a centrifugal point (not shown), and display element rows 3c-1, 3c-3 ,.
-N is formed to form a comet display configuration. As a matter of course, the display element array 3 may be arranged in the same manner as the conventional example shown in FIG.

FIG. 3 is a relationship diagram of the display unit 3, the digit driver 6, and the segment driver 7. Digit driver 6 is 1 for each frequency band (60Hz, 120Hz, ...)
A total of 14 pieces (DD _i , i = 0,1 ,, ..., 9, A, B, C, D) are provided, and the segment driver 7 has 13 pieces (SD _j , j = 0,1 ,, ..., 9, A, B, C) Then, each digit driver DD _i (i = 0 to D)
Is the digit signal Di (i = 0 to D) as shown in FIG.
Is driven in a time-divisional manner at time T intervals and periodically. In addition, each segment driver SD
_j (j = 0 to C) are respectively driven by the segment signals Sj (j = 0 to C) shown in FIGS. 4 to 8. It should be noted that the segment driver SD _{j is configured} to turn on the (j + 1) th display element from the top among the 13 display element rows. Further, S _o is a signal according to the maximum detection level (first detection level), S ₁ is a signal according to the second largest detection level, and generally S _m is the (m + 1) th signal. This signal corresponds to a large detection level.

Now, if the detection level of the signal identified by the level detection unit 1 is the maximum level among the 13 steps, the brightness control means 2b of the control microcomputer 2 causes the segment signal Sj (j) having a pulse width as shown in FIG. = 0 to C). The pulse width of the segment signal S _o according to the maximum level is the same as the pulse width of the digit signal Di, and thereafter, the pulse width of each segment signal is shortened by ΔT and becomes the minimum pulse width T _o . .

On the other hand, if the detection level of the signal determined by the level detection unit 1 is the second highest level, the brightness control means 2b
Is a segment signal having a pulse width as shown in FIG.
Sj (j = 0 to C) is generated, and if it is the third level, the brightness control means 2b generates a segment signal Sj (j = 0 to C) having a pulse width as shown in FIG. Similarly, if at the twelfth level, the segment signal Sj (j = 0 to C) having the pulse width as shown in FIG. 7 is generated, and at the lowest level, as shown in FIG. A segment signal Sj (j = 0 to C) having various pulse widths is generated.
That is, generally, assuming that the detection level is the m-th level from the top, the brightness control means 2b sets the pulse width of the segment signal S _m-1 corresponding to the detection level to T, and the following Δ
Segment signals S _m , S so that the pulse width becomes shorter by T
_{m + 1} , ..., S _c are generated and the segment signal S _o is generated.
Set the pulse width of ~ S _m-2 to zero.

The overall operation of FIG. 1 will be described below.

The timing control means 2a of the control microcomputer 2 generates the bandpass filter output switching signal BCS a predetermined time before the digit signal D _i (i = 0 to D) shown in FIG.

As a result, the signal Li of the i-th frequency band that has passed through the i-th band-pass filter BPFi is selected by the frequency time division circuit 1b and input to the level comparator 1c. It is determined and taken into the control microcomputer 2.

Thereafter, the brightness control means 2b of the control microcomputer 2 sets the i-th digit signal Di to a high level for a predetermined time T, and sets it to the detected i-th frequency band signal level (m-th level from the top). According segment signal
Suppose that the pulse width of S _m-1 is T, and segment signal S _m ,
The pulse widths of S _{m + 1} , ..., S _c are sequentially shortened by ΔT, and the pulse widths of the segment signals S _{o to} S _m-2 are set to zero.

As a result, in the display element array 3c-i (see FIG. 3) of the i-th frequency band in the display unit 3, the m-th display element from the top according to the detection level is driven to light for the time T, and The lighting drive time of the corresponding display element decreases by ΔT toward the lower level, and as a result, the brightness of the display element corresponding to the detection level becomes maximum, and the brightness of the display element decreases toward the lower level.

After that, if i is advanced by 1 at every time T and the above display control is performed for the entire band, the spectrum display is performed so that the display element corresponding to the detection level of each band becomes the brightest as shown in FIG. Be seen. In the display device of FIG. 2, the larger the black coating amount, the larger the brightness.

Thereafter, every time the display control in the above cycle is completed, the same display control is repeated with 1 → i.

In the above, the brightness control means 2b changes the brightness by controlling the lighting drive time, but it may be configured to control the drive voltage to control the brightness.

It is also possible to provide a display changeover switch on the operation unit 5 and to switch between the conventional spectrum display and the variable brightness display of the brightness control type by the switch.

Further, although the case where the present invention is applied to the spectrum analyzer display has been described above, the present invention is not limited to such a case.

<Effects of the Invention> According to the present invention as described above, a display unit is configured by arranging display element rows for level display for each frequency band, and
The signal level in each frequency band is detected, all the display elements from the lowest level to the detection level are turned on for each frequency band, and the brightness of the display element is decreased from the detection level toward the lowest level. Therefore, the frequency component can be displayed as if the upper limit display element (display element according to the detection level) is moving while leaving afterglow due to the level change. Ingredient display is now possible.

[Brief description of drawings]

FIG. 1 is a block diagram of a spectrum display device according to the present invention, FIG. 2 is an external view of a display unit, FIG. 3 is an explanatory view of the relationship between a display unit, a segment driver and a digit driver, and FIG. 4 is a digit signal and a segment. Waveform diagram of the signal, FIGS. 5 to 8 are segment signals according to the detection level
FIG. 9 is an external view of a conventional spectrum analyzer display, and FIG. 9 is a waveform explanatory view of S _{o to} S _c . DESCRIPTION OF SYMBOLS 1 ... Level detection part, 2 ... Control microcomputer, 2a ... Luminance control means, 2c ... Timing control means, 6 ... Digit driver, 7 ... Segment driver, 3 ... Display unit.

Claims (3)

[Claims] 1. A frequency component display device in which display element rows are arranged corresponding to each frequency band, and the level in each frequency band is displayed by each display element row. Level detection for detecting the level in each frequency band. And a brightness control means for turning on all display elements from the lowest level to the detection level and decreasing the brightness of the corresponding display element from the detection level to the lowest level. apparatus. 2. The frequency component display device according to claim 1, wherein the brightness control means controls the brightness according to the length of the lighting drive time. 3. The frequency component display device according to claim 1, wherein the brightness control means controls the brightness according to the magnitude of the lighting drive voltage.