JPH02214089A - Display device for level of signal in acoustic equipment - Google Patents

Abstract

PURPOSE:To clearly display level change even for a small signal level by applying weighing by logarithmic transformation on the maximum level of an acoustic signal detected at every prescribed period by using a microcomputer. CONSTITUTION:The acoustic signal processed by a signal processing circuit 3 is supplied to the microcomputer 12. And an acoustic level at every prescribed period is detected one by one, and also, the weighing by the logarithmic transformation is applied on a detected maximum level. Since the logarithmic transformation is applied, the change of the level even when the acoustic level is small can be displayed clearly. The signal on which the weighing is applied is supplied to a display unit 7, and the level of the signal can be displayed clearly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an audio signal level display device in an audio device such as a CD (compact disc) player that outputs an audio signal. This is suitable for displaying the level, and even if the level of the audio signal is low, it can be clearly displayed.

[Prior Art] Generally, the one shown in FIG. 2 is known as a CD player. Fig. 2 shows an outline of the signal system of a CD player, and in this figure, reference numeral 1 indicates a pickup,
2 is a high frequency amplifier, 3 is a signal processing circuit, 4 is a D/A converter, 5 is an amplifier, 6 is a microcomputer, 7 is a display, and 8 is a servo circuit, which are connected as shown in the figure. As the display 7, a bar meter or the like is used, for example.

In the CD player configured as described above, a signal picked up from a CD (compact disc) by a pickup 1 is amplified by an amplifier 2 and supplied to a signal processing circuit 3 and a servo circuit 8. Tracking, focusing, etc. of the pickup 1 are controlled by signals supplied to the servo circuit 8. The signal processed by the signal processing circuit 3 is converted into an analog signal by a D/A converter 4, amplified by an amplifier 5, and outputted from an output terminal 9 to the outside of the CD player. Further, the signal from the signal processing circuit 3 is supplied to the microcomputer 6, and the level of the signal (acoustic signal) is displayed on the display 7.

The signal supplied to the microcomputer 6 is as shown in FIG. 3, for example, and the maximum level (maximum value of the level of the acoustic signal magnitude) at the leap of the predetermined period t is detected,
This is displayed on the display 7 in units of stages of the magnitude of the acoustic signal.

Figure 4 shows which stage of sound signal magnitude the maximum level corresponds to every second according to changes in the level of the sound signal, and this stage is used as a unit as described above. It is displayed on the display 7.

In addition, if the above-mentioned microcomputer 6 does not include a D/A converter and an AC to DC conversion circuit, the signal is transmitted from the above signal processing circuit 3 via the D/A converter 4 and the AC to DC conversion circuit 1o shown by the chain line. An acoustic signal is input to a microcomputer 6, and a display 7 displays the level of this signal. In addition, the above D/A converter and AC →
In addition to the DC conversion circuit, if an A/D converter is not included, the signal processing circuit 3 to the D/A converter 4 is
, an AC to DC conversion circuit 10 shown by a chain line and A shown by a chain line
An acoustic signal is input to the microcomputer 6 via the /D converter 11, and the level of this signal is displayed on the display 7.

[Problems to be Solved by the Invention] As described above, if the change in the level of the acoustic signal is directly displayed as a level on the display, when the level of the acoustic signal is small, the change in the display in response to the change in level is small; It becomes difficult to clearly display changes in level. As mentioned above, this detects which stage of the sound signal magnitude the maximum level corresponds to every predetermined period according to changes in the level of the sound signal2, and uses this stage as a unit. The same applies when the level is displayed on the display 7 described above.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, as shown in FIG. 5, the acoustic signal level is displayed after being audibly corrected by logarithmic conversion or the like. be.

[Embodiments] Examples of the present invention will be described below with reference to the drawings. 1st
The figure shows one embodiment, and shows the main parts of FIG. 2 described above, and the same reference numerals as in FIG. 2 indicate the same parts. 12 is a microcomputer.

In FIG. 1, the acoustic signal processed as described above by the signal processing circuit 3 is supplied to the microcomputer 12, which detects the maximum level of the acoustic signal at each successive predetermined period, and calculates the detected maximum level logarithmically. Auditory perception is corrected by conversion, etc. This aurally corrected signal is supplied to the display 7, and the level of the signal is displayed.

Note that if the microcomputer 12 does not include a D/A converter, the output of the D/A converter may be supplied to the microcomputer 12 as shown by the chain line. The microcomputer 13 may receive a signal from the signal processing circuit 3, and the microcomputer 12 may output the signal to the display 7.

No. 21! all shows the second embodiment, and as in the case of FIG. 1, No. 21! Reference numeral 1 indicates the main parts of I, and the same reference numerals as in Fig. 1 or 2 indicate the same parts.
4 is a hearing correction circuit.

In FIG. 6, the acoustic signal output from the D/A converter 4 is subjected to auditory correction such as logarithmic conversion by the auditory correction circuit 14, and this output signal is transferred to the above-mentioned AC to DC conversion circuit 1.
Through 0 (or directly without passing through this as shown in the dashed line)
The signal is supplied to the microcomputer 6, and the maximum level is displayed on the display 7 for successive predetermined periods as described above.

FIG. 7 shows the third embodiment, and shows the main parts of FIG. 2 as in the case of FIG. 1, and the same reference numerals as in FIGS. indicates the same thing. code 1
5 is a microcomputer.

In FIG. 7, the acoustic signal output from the D/A converter 4 is input to the microcomputer 15, and in the microcomputer, when the value is smaller than the "value input to the microcomputer" in the table below, the "actual value" is The amount of change in the number of segments to be displayed is displayed in a large size, and when the value input manually to the microcomputer is large, the value is converted to a smaller value, and this converted value is displayed on the display 7. Ru.

Values manually entered into the microcomputer→ FIG. 8 shows the fourth embodiment, which is a bar meter (indicator) that shows the levels of the R (right) and L (left) channels of a stereo audio signal. Since this bar meter is designed to display the level every 3 dB for each unit bar, by supplying the signal from the conventional microcomputer 6 explained in FIG. 2 to the bar meter, logarithmic conversion is performed. This means that the auditory sense corrections have been made.

Note that the R and L levels may be displayed separately as in this bar meter, or the R+L level may be displayed.

FIG. 9 shows a fifth embodiment, in which the bar meter in FIG. 8 is replaced by a diagonally shaded segment among the seven segments that display numbers to display the level. . In this case as well, substantially the same effect as that in FIG. 8 can be obtained.

[Effects of the Invention] As described above, the present invention provides a CD that outputs an audio signal.
In an audio signal level display device in an audio device such as a player, the level of the audio signal is audibly corrected by logarithmic transformation etc., so that the level is clearly displayed even when the level of the audio signal is low. Therefore, it becomes easy to adjust the recording level when recording an output signal from a CD player or the like with a cassette tape recorder.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional example, FIGS. 3 and 4 are curve diagrams for explaining the operation of the device shown in FIG. 2, and FIG. is a diagram for explaining the signal level of this invention, FIG. 6 is a block diagram showing the second embodiment, FIG. 7 is a block diagram showing the third embodiment, and FIG. 8 is a block diagram showing the fourth embodiment. FIG. 9 is a schematic front view showing an example. FIG. 9 is a schematic front view showing a fifth embodiment. 12.15: Microcomputer, 14: Auditory correction circuit.

Claims (1)

[Claims] A signal level display device for an audio device that outputs an audio signal, characterized in that the level of the audio signal is audibly corrected by logarithmic transformation or the like and then displayed.