JPH0381670A - Level display device - Google Patents

Abstract

PURPOSE:To judge whether a level display is correct or not by providing a storage arithmetic circuit which warns that an input signal exceeds the maximum permissible input of an AD converting circuit. CONSTITUTION:The input signal which is applied to an input terminal 1 is adjusted by a variable resistor 2 for input signal level adjustment and its output is converted into a DC analog signal through a rectifier 3 and inputted to the AD converting circuit 4. The converted digital signal Vin is inputted to a storage arithmetic circuit 8. One end 5 of a variable resistor 6 for position detection is connected to a reference voltage and the output of its movable piece is converted by an AD converting circuit 7 into a digital signal VREF, which is inputted to a storage arithmetic circuit 8. The storage arithmetic circuit 8 has a peak holding function which converts the digital signal Vin logarithmically and stores a normal level meter display outputted to a display driving circuit 9 and the maximum value of the digital signal Vin and a function which discriminates the maximum permissible input over state of the AD converting circuit 4 and outputs a warning command.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a level display device for controlling input levels.

BACKGROUND OF THE INVENTION In recent years, microcomputer devices have made remarkable progress, and low-cost microcomputers of the type that directly drive an FL meter with a built-in D converter have appeared, and the scope of their use is expanding to a variety of devices. For example, FIG. 4 is a diagram showing a conventional example, in which an input signal entering an input terminal 1 is adjusted to an appropriate level by a first variable resistor 2, and a rectifier circuit 3 converts an AC signal into a DC signal. 9, the analog DC signal goes through the AD converter circuit 4 which converts it into a digital signal, and then the display is converted into a display that matches the scale of the level meter 10. The arithmetic circuit 8 calculates the logarithmic scale, etc., and the display drive circuit 9 This is a level display device that fully drives the level meter 10. MuD conversion circuit in it 4. Memory calculation circuit 82
There are also microcomputers 22 and the like in which display drive circuit 9 is integrated, realizing an inexpensive circuit configuration. Normally, it is also easy to store the maximum signal level p input so far in the storage/arithmetic circuit 8, calculate the maximum signal level/I/gold peak, and display it on the level meter 10.

Problem to be Solved by the Invention However, in the conventional example shown in FIG. 4, when an input signal exceeding the maximum allowable input value of the AD conversion circuit 4 is input to the AD conversion circuit 4, the peak hold value displayed on the level meter (The maximum signal level in one cabinet) is not the true maximum value (
Problem 4: AD conversion circuit 4 only shows saturated values
have.

The present invention solves the above problem, and when an input signal greater than the maximum allowable input is applied to the AD conversion circuit 4, the digital signal output is input to the storage calculation circuit 8, and the digital signal output is input to the storage calculation circuit 8. In order to exceed the digital signal level A/, a warning command is output from the storage/arithmetic circuit 8 to the display drive circuit 9, indicating that the peak hold value indicated by the level meter display is not the correct value. In other words, the user can easily determine whether the peak hold value indicated on the level meter topsoil is correct or incorrect by the warning display on the level meter display (for example, a blinking peak hold display segment or a separate warning display on the level meter display). The purpose is to provide a level display device @ that allows you to know the level.

Means for Solving the Problems In order to achieve this object, the level/level display device of the present invention is structured as follows.

An input terminal, a first variable resistor that changes the signal level Lv from the input terminal, a rectifier circuit that rectifies the output of the manually operated variable resistor, and a first AD that converts the output of the rectifier circuit into a digital signal. a conversion circuit, a second variable resistor whose one end is connected to a reference voltage and which has the same characteristics as the first variable resistor and is linked to the first variable resistor; and a second AD that converts the output into a digital signal. a conversion circuit; It is comprised of a storage/arithmetic circuit that stores and computes the digital signal of the second AD conversion circuit, and a display drive circuit that drives a level meter with the output of the computing circuit.

action The effects of the above structure are as follows.

The second variable resistor for position detection has the same characteristics as the first variable resistor for input signal level adjustment, and is interlocked with the first variable resistor. Even if the second variable resistor is operated and moved, the amount of change in the second variable resistor for position detection is proportional to the amount of change in the first variable resistor for adjusting the input signal level. The amount of change in the variable resistor is calculated using a memory calculation circuit,
By calculating the maximum signal level of the input signal stored in the memory calculation circuit according to the amount of change, the peak hold value on the level meter display can be moved in response to the movement of the variable resistor. By simply adjusting the peak hold value on the level meter display to the optimum recording level by operating the variable resistor, you can easily set the position of the variable resistor for manual adjustment to obtain the optimum recording level for a tape recorder, etc. I can do it.

Furthermore, when an input signal that exceeds the maximum allowable input of the first AD conversion circuit is applied to the first AD conversion circuit, the digital signal output is input to the storage calculation circuit, and the digital Since the signal level is exceeded, a warning command is output from the memory/arithmetic circuit to the display drive circuit, and operations such as flashing the peak hold segment of the level meter or flashing the warning display on the level meter display are performed. Inform the person that the peak hold value shown on the level/remeter display is incorrect.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a level display device according to a first embodiment of the present invention, and an input signal applied to an input terminal 1 is
The input signal level is adjusted to an arbitrary level by a variable resistor 2, and its output is converted to a DC analog signal that passes through a rectifier 3, and then converted to a digital signal by a D conversion circuit 4, and the converted digital signal Win is input to the storage arithmetic circuit 8. In order to drive the level meter 10 such as the FL rep N meter by the display drive circuit 9, the memory calculation circuit 8 logarithmically converts the input digital signal Win as shown in the flowchart of FIG. 2 (&). There is a normal level meter display that outputs the output to the display drive circuit to perform level meter display, a peak hold function that stores the maximum value of the digital signal Win input in the past, which will be described in detail later, and a peak hold function that stores the maximum value of the digital signal Win input in the past, which will be described in detail later. It has an over-permissible input identification function that identifies the maximum digital signal output of the digital converter circuit 4 when the maximum allowable input of the AD converter circuit 4 is exceeded, and outputs a warning command at that time, and outputs a warning command to the display drive circuit 9. A warning is displayed on the level meter 10 after passing the money.

The peak hold function of this embodiment stores the maximum digital signal input to the past storage calculation circuit 8 as in the conventional case.
Not only can the peak hold segment be lit on the level meter 10 through the display drive circuit 9, but the peak hold segment can also be linked to the movement of the input level adjustment variable resistor 2, allowing the optimum recording level for tape recorders, etc. In order to adjust the input level adjustment variable resistor 2 to the previous peak hold segment on the level meter 10, set the level on the level meter to /1/'! By operating the input level adjusting variable resistor 2 so that the optimum recording level μ is achieved while watching i=the position of the input level adjusting variable resistor 2 is set to the optimum recording level. This is due to the function of the position detection variable resistor 6 which is linked to the input level adjustment variable resistor 2 and has the same characteristics. The details will be explained below.

One end 5 of the variable resistor 6 for position detection is connected to a reference voltage, and the output d of the movable piece is inputted to an AD conversion circuit 7, converted into a digital signal VRXF, and inputted to a storage calculation circuit 8. The storage arithmetic circuit 8 stores a resistor μ signal VRXFf as position information of the position detection variable resistor 6. Here, since the position detection variable resistor a6 and the input signal level A/adjustment variable resistor 2 are linked, the setting position of the position detection variable resistor 6 is the input signal level adjustment variable resistor 2. This is the same as the setting position. Also, since the characteristics of the position detection variable resistor 6 and the input signal level adjustment variable resistor 2 are the same, the output change rate of the position detection variable resistor a6 and the output change of the input signal level adjustment variable resistor 2 are the same. The rate will be the same.

This will be explained using Figure 3 of the Golden Brother.

The horizontal axis in FIG. 3 is the position of the variable resistor, and the vertical axis is the output of the variable resistor 2 for adjusting the input signal level and the output of the variable resistor fig for position detection. Let the outputs of variable resistor 2 and variable resistor 6 when the variable resistor is at point a be Vina and VRxya, respectively.

Next, when the position of the variable resistor moves to point b, all outputs of variable resistor 2 and variable resistor 6 are VinbVutrb, respectively.
Then, since the characteristics, that is, the slopes of the variable resistor 2 and the variable resistor 6 are equal, the rate of change in the output of the resistor 6 and the rate of change in the output of the input signal level adjusting variable resistor 2 are equal. This is because if the rate of change in the output of the variable resistor 6 for position detection is known, then the change in the variable resistor 2 for adjusting the input signal level can be calculated backwards. Although FIG. 3 shows a characteristic iB curve of a variable resistor, the same can be said of a non-linear curve such as a MU curve.

Next, the operation of the peak hold function of the present invention will be explained with reference to the flowchart i in FIG. 2(b).

Without the housing, set the 2-metal metal variable resistor for input level adjustment at an arbitrary position, for example, at a position hole. At this time, the position detection variable resistor 6 is linked to the input level adjustment variable resistor 2, so
The position detection variable resistor 6 is also located at the same position a.

The input signal adjusted by the input level adjustment variable resistor 2 is rectified by the rectifier 3 and converted into a DC analog signal, and then converted into a digital signal by the AD conversion circuit 4.

Then, the digital signal Wi converted by the AD conversion circuit 4
n is read into the memory calculation circuit 8 as an input signal (
Step a).

The storage arithmetic circuit 8 compares the values of Win that are read out one after another and stores the largest value Mi as the maximum value (step b). Further, the storage/arithmetic circuit 8 logarithmically transforms this maximum value M'i (step C), outputs it to the display drive circuit 9 for display (step d), and lights up the peak hold segment on the level meter 1o as the peak hold value.

Next, the storage/arithmetic circuit 8 reads the position signal V*mye obtained by converting the movable piece output of the position detection variable resistor 6 into a digital signal by the AD conversion circuit 7 (step e).

Since the current position detection variable resistor 6 is at position a,
The position signal VRIF becomes V*ZV &. 8tets7”r
Here, it is detected whether the position of the interlocking variable resistor 2.6 has been changed by the user, and if it has not been changed, the process returns to step a and the ninth input signal Win is read. The position of variable resistor 2.6 is changed.
For example, if there is a change from position a to position, move to step °g and multiply by the rate of change k (step h).
Furthermore, the process of replacing the maximum value M with MXk (step 1)
After doing so, return to step b and repeat the above steps.

Therefore, the user can display 1tl of the logarithmically transformed maximum value V.
Not only can og and it be checked on the level meter 10, but by changing the positions of the interlocking variable resistors 2 and 6, the maximum value V is replaced by MXk according to the rate of change k, and this Logarithmic transformation value log of the replaced value
M X k will be instantly displayed on the level meter 1o.

As described above, according to this embodiment, the maximum value V of the input signal Win is peak-held and displayed on the level meter 10, and the displayed value on the level meter 10 is changed according to the position change of the interlocking variable resistor. (Peak hold value) also changes, so when the user sets the optimal recording repeat A/F of a tape recorder, for example, the user can extremely easily and accurately set the level while visually checking the display @ on the level meter 10. I can do it. Note that even if the characteristics of the variable resistors 2 and 6 are different, the same effect can be obtained by pressing the button on the memory calculation circuit 8 and correcting the difference in characteristics.

Next, a warning display will be displayed on the meter 10 when the maximum allowable input of the AD conversion circuit 4 is exceeded. (0) in FIG. 2 is a maximum allowable input over warning flowchart. The storage/arithmetic circuit 8 reads the output Win of the AD conversion circuit 4 and determines whether it exceeds the internally set value x2. The set value X is preferably set to the maximum digital signal value of the AD conversion circuit 4. Memory calculation circuit 8
If the set value x2 is not exceeded, the process returns to reading the input signal, and when the set value X is exceeded, that A/-) is passed. When the set value X is exceeded, the storage/arithmetic circuit 8 outputs a warning display, and a warning display is displayed on the level meter 10 through the display drive circuit 9. Various warning display methods can be considered, such as flashing a peak hold segment on the level meter 1o, or providing a separate warning display on the level meter 10.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described in detail, a variable resistor for adjusting a signal level for an input signal, a variable resistor for position detection linked thereto, and an output of each variable resistor are converted into a digital signal. an AD conversion circuit; a storage calculation circuit that stores or logarithms the respective digital signal values and calculates a maximum permissible input over-input warning for the AD conversion circuit of the input signal;
A display drive circuit that displays the output of the memory calculation circuit on the level meter displays the maximum value of the input signal (peak hold display) and displays the peak hold segment on the level meter in accordance with the movement of the variable resistor. By moving the peak hold segment on the level meter to match the optimum recording rep N of a tape recorder or the like, the variable resistor for adjusting the input signal level can be adjusted very easily.

The peak hold value on the level meter is AD
If the maximum permissible input of the conversion circuit is exceeded and the value is incorrect, the peak hold segment flashes to indicate a warning, so the user can always quickly determine whether the current peak hold value is correct or incorrect. Display device gold can be realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the level display device of the first implementation column of the present invention, FIG. 2 is a flowchart explaining the operation of FIG. 1, and FIG. 3 shows the first variable resistor and the second variable resistor. The characteristic diagram of the resistor, FIG. 4, is a block diagram of a conventional example. 1... Input terminal, 3... Rectifier circuit, 5...
...Reference 1fE terminal, 2.6...Variable resistor, 4,7...AD conversion circuit, 8...Note...
is an arithmetic circuit, 9...display drive circuit, 10...
...Level meter.

Claims (1)

[Claims] an input terminal and a first variable resistor that varies the signal level from the input terminal; a rectifier circuit that rectifies the output of the first variable resistor; and a first variable resistor that converts the output of the rectifier circuit into a digital signal. a second variable resistor having one end connected to a reference voltage and interlocking with the first variable resistor, and a second AD converting circuit that converts the output of the second variable resistor into a digital signal. A conversion circuit, a storage calculation circuit that stores and calculates the digital signals of the first and second AD conversion circuits, and a display drive circuit that drives a level meter with the output of the storage calculation circuit; The signal level corresponding to the maximum input value of the input signal is stored in a memory calculation circuit,
In addition to displaying the signal level on the level meter, the positions of the first and second variable resistors are stored in a memory calculation circuit by the output of the second variable resistor, and the signal level corresponding to the stored maximum input value is displayed. , based on the positions of the first and second variable resistors, the memory calculation circuit calculates the values on the level meter according to changes in the operating positions of the first and second interlocking variable resistors. moving the signal level display corresponding to the maximum input value, and when an input signal level equal to or higher than the maximum allowable input value of the first AD conversion circuit is input to the first AD conversion circuit;
The digital output of the first AD conversion circuit is input to the storage calculation circuit at a level exceeding the digital signal level set in the storage calculation circuit, and the maximum allowable input from the storage calculation circuit to the first AD conversion circuit is exceeded. A level display device characterized by transmitting a warning command to a display drive circuit and displaying a warning on a level meter display.