JPH0145033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a display device for a frequency analyzer, such as a spectrum analyzer, that displays the level of each frequency band of an acoustic signal.

Configuration of Conventional Example and Its Problems Conventionally, display devices have been known that divide an acoustic signal or the like into frequency band components and display the level of each frequency band component.

However, these conventional display devices only display the instantaneous level of each frequency band component in the form of a bar graph, and have the disadvantage that they cannot display how the peak value of each frequency band changes. .

Purpose of the Invention The present invention eliminates the above-mentioned drawbacks of the conventional technology, and provides a frequency analyzer that can display instantaneous level changes of each frequency band component and changes in peak value of each frequency band component at predetermined time intervals. The present invention provides a display device.

Structure of the Invention In order to achieve the above object, the present invention includes means for displaying the peak value for each frequency band, and means for sequentially lowering the peak value display when the peak value decreases. According to the present invention, the state of change in the peak value of each frequency band and the degree of decrease in the peak value can be grasped at a glance.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows a display section of a display device in an embodiment of the present invention. In this example, the acoustic signal is divided into seven frequency bands (center frequency 65Hz, 250Hz, 500Hz,
1KHz, 1.8KHz, 4KHz, 10KHz) and displays the level of each frequency band in the form of a bar graph using 13 display elements (light emitting diodes, etc.). This embodiment displays the instantaneous level of each frequency band component in the form of a bar graph (blacked out areas in Fig. 1 indicate display elements that emit light), and also displays the instantaneous level of each frequency band component at predetermined time intervals. The peak value at is displayed by light emission (the shaded area in FIG. 1 indicates the light emission of the display element indicating the peak value).

FIG. 2 shows the circuit configuration of this embodiment. In Fig. 2, 2 is an adder that adds the right channel signal R and the left channel signal L, 3 is an amplifier that amplifies the added signal, and BPF1 to BPF7 have center frequencies of 65Hz, 250Hz, 500Hz, and 1KHz, respectively.
1.8KHz, 4KHz, and 10KHz frequency band filters (bandpass filters), 4 are controlled by control signals from the control unit 5;
Sequentially select the output signals of BPF1 to BPF7 and
This is a data selection circuit that supplies data to the D converter 6 . The bandpass filter output selected by the data selection circuit 4 is converted into a digital value by the A/D converter 6 and input to the comparison circuit 7 . This comparison circuit 7
Then, the output of the A/D converter 6 is compared with 13 different fixed levels, and the comparison results are output. That is, in the comparator circuit 7, the A/D
The converted value and 13 fixed levels are compared, and if the A/D converted value is lower than the fixed level, "H" is output to the corresponding output terminal,
Furthermore, when the A/D conversion value is higher than the fixed level, "L" is output to the corresponding output terminal.
A plurality of (13) outputs of the comparison circuit 7 are input to the control section 5 via the multiplexer 8. The control unit 5 includes a central processing unit (CPU), read-only memory (ROM), and random access memory (RAM).
Consists of etc. Reference numerals 9 and 10 are driver circuits that supply current to the light emitting diodes constituting the diode matrix circuit 11 to turn on and off the light emitting diodes. The driver circuit 10 sequentially outputs "H" to a plurality of (seven) output terminals in a predetermined order based on a control signal output from the control section 5. The output terminal from which “L” is output from the driver circuit 9 and the driver circuit 10
The light emitting diode in the diode matrix 11 connected to the intersection with the output terminal where "H" is output lights up, and the instantaneous level of each frequency band shown in Fig. 1 is displayed ( (The blacked out area in Figure 1). 12 is a demultiplexer, a hold signal output from the control unit 5 is applied to the demultiplexer 12, and "L" is output to a predetermined output terminal of the demultiplexer 12 for a predetermined time (about 2 seconds), and the diode matrix The light emitting diode corresponding to the peak value of Tx 11 lights up to display the peak value level (shaded area in FIG. 1). Also, if the peak value level decreases,
A decreasing switching signal is sequentially outputted from the control unit 5 to the demultiplexer 12, and the peak value display is sequentially switched in a "raindrop" style (about every 0.1 second). That is,
When the sequential decrease switching signal is applied to the demultiplexer 12, "L" is sequentially output from the output terminal corresponding to the peak value at which "L" is output to the output terminal corresponding to the low level, and as shown in FIG. The peak value display shown in is successively shifted downward.

FIG. 3 shows the functional blocks of the control section 5. In FIG. 3, 13 is a previous peak value register in which the previous peak value B is stored, and 14 is a peak value detection means for detecting the peak value of the current level output from the multiplexer 8. The current peak value A detected by the means 14 is stored in the current peak value register 15.
16 is a comparison means for comparing the previous peak value B and the current peak value A, and 17 is a data rewriting means. If the result of the comparison by the comparison means 16 is that the current peak value A is larger than the previous peak value B, the data is The rewriting means 17 writes the current peak value A in place of the peak value B in the previous peak value register 13. 18 is a timer means, and this timer means 18, by comparison by the comparison means 16,
It is set when it is determined that the current peak value A is larger than the previous peak value B. timer 18
While the timer 18 is set (approximately 2 seconds), the hold signal generation means 19 outputs a hold signal, but when 2 seconds have elapsed since the timer 18 was set, the decrease switching signal generation means 20 sequentially outputs the decrease switching. A signal is output. In addition, Figure 3 shows the peak value display in one band and the “raindrop type”
Only the displayed functional blocks are shown, and in the above embodiment, there are seven bands of functional blocks similar to the functional blocks shown in FIG.

FIG. 4 is a flowchart of the functional block shown in FIG. 3. In step a, it is determined whether the current peak value A is larger than the previous peak value B, and the current peak value A is larger. If it is determined that this is the case, a timer is set in step b, and the peak value data is rewritten in step c. When the processing in step c is completed, or in step a, the current peak value A is
When it is determined that is smaller than the previous peak value B,
In step d, the set timer reaches 2.
It is determined whether or not seconds have elapsed. If 2 seconds have not elapsed, the process returns to step a. If it is determined in step d that 2 seconds have elapsed, a sequential switching operation (raindrop type display) is executed in step e. This returns to step a.

FIG. 5 shows the display device (first
The display element group in the third column from the left (center frequency
It shows the display changes over time of the display element group for displaying the 500Hz frequency component level. At time t ₁ , the peak value is +6 dB and the current signal level is -
It is displayed that it is 4dB. The display element displays the time t ₁ → t ₂ → t ₃ → t ₄ ...tn → tn ₊₁ → tn ₊₂ →
It changes as shown in Figure 5 as tn ₊₃ progresses. If the current signal level does not become larger than the peak value (6 dB) of t ₁ during 2 seconds from time t ₁ , then 2
The second peak value display (shaded area) does not change, and the signal level display (blacked out area) changes moment by moment. When two seconds have elapsed from time _t1 , as is clear from FIG. 4, the sequential switching display operation (raindrop type display) of peak values is started. In FIG. 5, tn ₊₁ to tn ₊₃ show the sequential switching display operation of peak values. When the sequential switching display operation is started, as shown at tn ₊₁ , at tn ₊₁ , the display element that displays the peak value +6 dB goes out, and the display element that displays the peak value +4 dB lights up. At time tn ₊₂ , the display element that displays +4 dB goes out, and the display element that displays +2 dB lights up. Furthermore, at time tn ₊₃ , the display element that displays +2 dB goes out, and the display element that displays 0 dB lights up. In this way, after 2 seconds have elapsed from _t1 , the lighting of the display elements that display the peak value gradually shifts to the lower level side in a raindrop manner.

As described above, according to this embodiment, the instantaneous and instantaneous levels of each frequency band are displayed, and the peak value of each frequency band at a predetermined time is displayed, so changes in the peak value can be understood at a glance. be done. According to this embodiment, when the peak value decreases after a predetermined period of time, the peak value display decreases like a raindrop, so there is an advantage that the degree of change in the peak value can be visually grasped.

Effects of the Invention According to the present invention, there is an advantage that not only instantaneous level changes but also changes in the peak value of each frequency band and the extent of the change in the peak value can be easily grasped.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a display section of a display device for a frequency analyzer according to an embodiment of the present invention, FIG. 2 is a block diagram of the same device, and FIG. 3 is a functional block diagram of a part of the control section of the same device. FIG. 4 is a flowchart of the same functional block, and FIG. 5 is a diagram showing changes in the display state of the device. 1... Display element, 2... Adder, 3... Amplifier, BPF1 to BPF7... Frequency band filter (band pass filter), 4... Data selection circuit,
5... Control unit, 6... A/D converter, 7... Comparison circuit, 8... Multiplexer, 9, 10... Driver circuit, 11... Diode matrix,
12...Demultiplexer, 13...Previous peak value register, 14...Peak value detection means, 15...
...Current peak value register, 16...Comparison means, 1
7... Data rewriting means, 18... Timer means, 19... Hold signal generating means, 20... Sequential decrease switching signal generating means.

Claims (1)

[Claims] 1 means for dividing an input signal into a plurality of frequency band components; a display section having a plurality of display elements arranged vertically and horizontally; means for displaying the level of each frequency band component of the input signal on the display section; means for displaying the peak value of each frequency band component level of the input signal on the display section for a predetermined period of time; and means for displaying the peak value on the display section when the peak value of each frequency band component of the input signal decreases. 1. A display element for a frequency analyzer, comprising a lighting switching means for sequentially switching lighting on display elements on a lower level side than a display element on the lower level side.