JPS599099B2 - level display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a level display device suitable for use as a level indicator of a tape recorder, for example, and an object of the present invention is to simultaneously and accurately display the average level and peak level of a signal whose level is to be displayed. The purpose is to make it readable.

Conventional level display devices are configured to display the average level of a signal using a vU meter and the peak level by lighting a light emitting diode, taking the level display of a tape recorder as an example. That is, changes in the average level of the signal are indicated by the deflection of the pointer of the VU meter, and pulsed signals that cannot be tracked by the meter are indicated by lighting a light emitting diode. However, in this type of display device, the average level and peak level are displayed in different ways, so it is difficult to read both levels at the same time, and the peak level is displayed only when a signal exceeding a preset level value is input. The disadvantage is that it is difficult to understand the relative relationship between the average level and the peak level unless you memorize the level value when the light emitting diode lights up in advance. It was hot.

Regarding the ability to read the average level and peak level at the same time, conventionally a meter with two needles was used, and the deflection of one needle was used to display the average level, and the deflection of the other needle was used to display the peak level. However, because the two pointers swing in a complicated manner, it is difficult to distinguish and read the two levels, and mechanical problems such as a delay in the rise of the pointer relative to the signal and overshoot occur. The instructions were inaccurate and undesirable, as there were also problems with the structure of the system.

Therefore, the present invention solves such conventional drawbacks and problems, and it is possible to read the average level and peak level of a signal at the same time without using a meter that displays the level by the movement of a pointer. The object of the present invention is to provide a level display device that can display the level of the level and clearly distinguish between the two levels of display.One embodiment of the device will be described below with reference to the drawings. FIG. 1 shows the basic circuit configuration of the device of this embodiment. A signal to be level-displayed is applied to a buffer amplifier 2 via an input terminal 1, where appropriate signal amplification and impedance conversion are performed. .

The output of the amplifier 2 is applied to the input terminals of two rectifying and smoothing circuits 3a and 3b. The above two rectifying and smoothing circuits 3a, 3
Among the circuits 3b, one circuit 3a has its charging/discharging time constant set to correspond to the average value of the input signal, and the other circuit 3b has a time constant set to correspond to the peak value. The outputs of the two rectifier circuits 3a and 3b are respectively applied to the input terminals of voltage comparator groups 4 and 5 each comprising a plurality of voltage comparators whose threshold values are set in order in terms of levels. The voltage comparator group 5 is configured to output only the output corresponding to the voltage comparator having the closest value to the output of the rectifier circuit 3b. A plurality of output terminals C, ~Cn, D, ·B, ~Dn-, · of each of these voltage comparator groups 4 and 5
Bn-,,Dn are applied to the OR circuits 6, 6n for every two corresponding outputs, for example, C, and D, ・B, ,C, and D, ・B, ,Cn and Dn. mixed. The outputs of the plurality of OR circuits 61 to 6n are 1 of the light emitting display.
A plurality of anode electrodes A, ~An of the fluorescent display tube 7
are connected to each. With this configuration, when an audio signal with a waveform including the pulse component X as shown in the figure is applied to the input terminal 1, this signal is applied to the rectifying and smoothing circuits 3a and 3b through the buffer amplifier 2,
- The average level m of the above signal from the rectifying and smoothing circuit 3a
The other rectifier circuit 3b outputs a voltage corresponding to the peak level p of the signal.

The outputs of the voltage comparison group 4, for example C, to C6, are obtained by the output of the one rectifying and smoothing circuit 3a,
For example, Dl of the voltage comparator group 5 is determined by the output of the other rectifier circuit 3b.・B. Assuming that outputs are obtained from the terminals of , these outputs are applied to multiple OR circuits and mixed, so that
. emits an output. These outputs are the anode electrodes A to A6 and A of the fluorescent display tube 1. These anode electrodes emit light when applied with . As shown in FIG. 2, when the anode electrodes A, -An are arranged in a rectangular line in the horizontal direction, from electrode A at the left end to electrode A. As well as emitting light, the electrode Al. emits light, so the average level m from the left end electrode A1 to the electrode A6 position is - in the figure.
5dB) displayed, electrode A,. The peak level p (5 dB in the figure) is displayed at the light emitting position, and both levels can be easily read simultaneously and clearly distinguished. Since the number of the electrodes that emit light changes as the average level of the input signal increases, the user feels as if the length of a long line is changing, and can grasp the transition of the average level in a natural way. Since the electrode is caused to emit light at a spot away from this average level position, the transition of the peak level can be easily grasped by moving this light emitting point. In addition, if the output voltage of the voltage comparator group 4 is set lower than the output voltage of the voltage comparator group 5, the luminance of the electrodes A, -A6, which display the average level in the above embodiment, will be as shown in FIG. Electrode A, which displays the peak level as follows.

The luminance is lower than the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance of the luminance. The above is a description of the general structure and operation of the apparatus of this embodiment. Next, each structure will be explained in detail using the drawings from FIG. 3 onwards.

First, using FIGS. 3 and 4, the rectifying and smoothing circuits 3a, 3
The configuration of b and how to determine its time constant will be explained. As shown in FIG. 3, one rectifying and smoothing circuit 3a has a resistor R. ，
, Rv, . Rectifier diode Dc Smoothing capacitor C
The other rectifying and smoothing circuit 3b includes a rectifying diode Dc, a smoothing capacitor Cp, and a resistor R. Therefore, the rising time of the rectifying and smoothing circuit 3a is mainly determined by the time constant RCI-CV, the falling time is mainly determined by the time constant CvRv, and the rising time of the rectifying and smoothing circuit 3b is determined by the output of the buffer amplifier 2. The time constant is determined by the impedance z (which is a very small value), the forward resistance of the diode Dc, and the capacitor Cp, and the fall time is determined by the time constant Cp-Rp. Therefore, the rise time of the other rectifying and smoothing circuit 3b is selected to be sufficiently short (early) compared to the rising time of one of the rectifying and smoothing circuits 3, and the falling time of the other rectifying and smoothing circuit 3b is selected to be sufficiently short (earlier) than the rise time of one of the rectifying and smoothing circuits 3a. If the fall time is selected to be sufficiently long (slow) compared to the fall time of , when a signal with the waveform shown in curve 8 in FIG. The voltage appearing at the output terminal 9 of one rectifying and smoothing circuit 3a becomes as shown by a curve 10a, and the voltage appears as shown in a curve 9a. That is, the output of one rectifying and smoothing circuit 3a becomes the average level of the input signal, and the output of the other rectifying and smoothing circuit 3b becomes the peak level. Next, FIG.
111 to 11n indicate a plurality of voltage comparators constituting the voltage comparator group 4, 12, to
12n and 13, to 13n-1 are a plurality of voltage comparators constituting the voltage comparator group 5, and the voltage comparators 11, to 13n-1 are
The positive input terminals of the voltage comparators 121 to 12n and the negative input terminals of the voltage comparators 131 to 13n- are all connected to the terminal 10. It is connected.

And the voltage comparators 111 to 11n and 121 to 12n
The negative input terminals of the voltage comparator 1 are connected to potential points obtained by dividing the DC power supply E2 by the resistors R1 to Rn+1.
Voltage comparators 11n, 12 from the negative input terminals of 11, 121
The applied voltage is gradually increased toward the negative input terminal of n, and the threshold value thereof is gradually increased. On the other hand, the positive input terminals of the voltage comparators 131 to 13n-1 are connected to potential points one step higher than the voltage comparators 111 to 11n and 121 to 12n. That is, for example, voltage comparator 111
, 121 is connected to the connection point between the resistors R1 and R2, while the positive input terminal of the voltage comparator 13 is connected to the resistor R
2 and R3 are connected to each other. Moreover, the power supply voltage of the voltage comparators 111 to 11n is the DC power supply E2.
voltage comparators 121-12n and 131
The power supply voltage of ~13n-1 is provided by the DC power supply E3 having a higher voltage than the DC power supply E2. Therefore, when a signal is applied from terminals 9 and 10 to the input terminals of voltage comparators 4 and 5, if the level is the threshold of each voltage comparator, for example voltage comparators 111 and 12, then the voltage of resistor R1 is When the voltages at both ends are exceeded, the outputs of these voltage comparators 111 and 121 are at the level of the power supply voltages E2 and E3, respectively.On the other hand, when the voltages at both ends are exceeded, the outputs are at the level of the ground potential and, for example, in the case of the voltage comparator 131, the outputs of the resistors (R1+R
When the voltage across both ends of 2) is exceeded, the output becomes the ground potential level, and conversely, when the voltage is below the threshold voltage, the output becomes the power supply voltage E3.
level. Therefore, in the voltage comparator group 4, a plurality of voltage comparators up to the voltage comparator with the threshold closest to the level of the input signal simultaneously output the voltage E2, but in the voltage comparator group 5, the voltage comparator 12n outputs the voltage E2 at the same time. For example, since each output of opposing devices such as voltage comparators 121 and 131 is passed through AND circuits 141 to 14n-1, the AND circuits on the output sides of the two voltage comparators have thresholds that are very close to the input signal level. The output of voltage E3 is made to be emitted only from the terminal. A plurality of output terminals C1 to Cn, Dl/B1 to Dn-1/Dn of each of the voltage comparator groups 4 and 5
-1 and Dn are OR circuits 6 and 6, respectively.

The anode electrode A of the fluorescent display tube 7 is commonly connected through the
~An, and one filament F of the fluorescent display tube 7 is heated by a DC power source E1. Therefore, the signals applied from terminals 9 and 10 to the input terminals of voltage comparator groups 4 and 5 cause i voltage comparators 11 to be connected in order from the lowest to lowest.
Outputs 1 to 11i and j voltage comparators 12 in order from the lowest
1 to 12j (where 1≦1<j≦n) respectively change from the ground potential to the potential of the power supply voltages E2 and E3. In this case, the outputs of the voltage comparators 131 to 13, -1 are at the ground potential, Only the output of the voltage comparator 13 is the voltage E
3, the voltage E3 is output only from the AND circuit 14j.

From the potential E1 of the filament F of the fluorescent display tube 7, the anode electrodes A, .about.Ai. 15Aj becomes sufficiently high, electrons emitted from filament F collide with anode electrodes A1 to Ai<15Aj, and excite the phosphor coated on the electrodes, causing them to emit light. At this time, anode electrode A1~
Since the potential E2 of Ai is lower than the potential E3 of the anode electrode AjO, the potential difference between the electrodes A1 to Ai and the filament F is smaller than the potential difference between the electrode Aj and the filament F. Due to the nature of a fluorescent display tube whose luminance changes approximately proportionally, the electrodes A1 to Ai emit light darker than the electrode Aj. Then, the average level and peak level are displayed as shown in FIG. In the above embodiment, the case where the average level and peak level of one signal are displayed was explained, but if there are two or more signals whose levels should be displayed, the circuit system shown in Fig. 1 should be prepared according to the number of signals. Just do it.

Further, the fluorescent display tube 6 in the above embodiment can be easily replaced with a light emitting diode or the like formed by incorporating a plurality of light emitting chips in the same case. As explained above, according to the level display device of the present invention, the following effects can be obtained.

(1) Since a light-emitting display with multiple light-emitting elements is used as a level indicator, it is easier to manufacture and has a comparatively better design compared to conventional VU meters that have a mechanical structure. Can be changed freely. Moreover, unlike conventional VU meters, there is no problem of poor followability of the pointer signal due to the mechanical structure, such as delay in rising of the pointer or overshoot, and it is possible to display a level that accurately follows the signal. (2) A further characteristic effect is that the average level and peak level of the signal are displayed simultaneously on the same display screen, and the average level is displayed as a change in the length of a straight line, and the peak level is displayed as a movement of a point. It is recommended that the information be displayed separately from tsuri.

As a result, although there was a peak indicator in the past, its display method was different from the display method for the average level, so in effect, only the average level was monitored, and distortions etc. at the peak level were overlooked. This problem can be solved at once.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a level display device according to an embodiment of the present invention, FIG. 2 is a diagram illustrating an example of display by the same device, and FIG.
The figure is a circuit diagram of the rectifying and smoothing circuit part that makes up the device.
The figure is a comparison waveform diagram of the input signal and the output voltage obtained by the above circuit, and FIG. 5 is a circuit diagram showing the connections of the voltage comparator group, OR circuit, and fluorescent display tube constituting the above apparatus. 1... Input terminal, 3a, 3b... Rectifier and smoothing circuit, 4, 5... Voltage comparator group, 61-6
n...OR circuit, 7...fluorescent display tube,
111-11.

Claims (1)

[Claims] 1 A first rectifying and smoothing circuit outputs an AC signal to be displayed at a level by setting a charging/discharging time constant to a DC level corresponding to a DC level corresponding to the average level of the input signal, and a first rectifying and smoothing circuit with a charging/discharging time constant different from the above. A plurality of voltage comparators whose threshold values are set to apply the voltage to a second rectifying and smoothing circuit that outputs a DC level corresponding to the peak level of the input signal according to settings, and threshold values of the output of the first rectifying and smoothing circuit are set in order of level. and the output of the second rectifying and smoothing circuit is applied to a group of voltage comparators composed of a plurality of voltage comparators and a Gout circuit whose threshold values are set in order in terms of levels, and the output of the second rectifying and smoothing circuit is The voltage is applied to a second voltage comparator group which outputs only the output corresponding to the voltage comparator having a threshold value closest to the output of the rectifying and smoothing circuit, and a plurality of the first and second voltage comparator groups The outputs are applied to an OR circuit every two outputs that correspond to each other in terms of level, and the outputs of these OR circuits are applied to a plurality of light emitting elements arranged in order in terms of level, corresponding to the threshold level of the voltage comparator group. A level display device that applies voltage.