JPH0435772B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a signal generating device that generates a signal. In particular, it is an object of the present invention to provide an improved signal generating device that can specify a range in which a signal can be output with good linearity.

[Prior Art] In a signal generating device that generates one type of waveform or a signal generating device that generates many types of waveforms (for example, triangular wave, sine wave, square wave, etc.), it is possible to superimpose an offset. There is something. However, when varying this offset, the dynamics of the output circuit of the signal generator
There were cases where the range (the range in which signals can be output with good linearity) was exceeded, resulting in distorted signals.

[Problems to be Solved by the Invention] When the offset superimposed on a signal is varied, it may exceed the dynamic range of the output circuit of the signal generator and the signal may be distorted. When using for measurement,
This sometimes caused serious measurement errors.

This situation occurs because the amplitude of the signal is variable;
Since the offset superimposed on it is also variable,
When both of them are arbitrarily varied, a situation arises in which part of the signal waveform exceeds the dynamic range, which has only a fixed range. In order to avoid such a situation, the signal generator must be used while monitoring the signal waveform with an oscilloscope or the like, which is extremely inconvenient.

[Means for Solving the Problems] The present invention has been made to solve these problems, and includes an indicator that indicates a certain dynamic range, and in which the output signal is It has been made clear what range is in.

a generation circuit that generates a signal; an amplitude adjustment circuit that receives the signal and adjusts its amplitude in accordance with the instructions of the first control signal; and a second circuit that receives the output of the amplitude adjustment circuit. an output circuit for superimposing an offset according to the instruction of the control signal; an indicator for positionally displaying the amplitude of the signal in the dynamic range according to the instruction signal; and first and second control signals and the instruction signal. A control circuit that generates .

[Function] A dynamic range is stored in advance in the control circuit, and the control circuit that outputs the first control signal for adjusting the amplitude of the signal and the second control signal for instructing the value of the offset uses this amplitude. By calculating the value of the dynamic range and the offset value, it is calculated in which range of the dynamic range the signal exists, and an instruction signal is applied to the indicator, thereby clearly indicating the relationship between the dynamic range and the signal.

This allows you to use this indicator to know when a signal exceeds the dynamic range without having to connect an oscilloscope or other device as a monitor, ensuring that there is no risk of making serious errors in measurements. Now I can avoid it.

[Embodiment] A circuit configuration diagram showing an embodiment of the present invention is shown in FIG. 1, and a display screen for explaining the operation is shown in FIG. 2, and the explanation will be made using these.

10 indicates the type of waveform (triangular wave, sine wave, square wave, etc.) instructed by the control signal 33, the frequency,
This is a signal generation circuit for generating a signal waveform 41 in response to data for specifying a signal such as a duty cycle.

12 receives the signal waveform 41 and outputs the control signal 3
5 is an amplitude adjustment circuit for obtaining a signal waveform 42 having an amplitude indicated by 5.

13 receives the signal waveform 42 and outputs the control signal 3
This is an output circuit for superimposing the offset indicated by 6 and outputting it to the output terminal 20.

Reference numeral 15 denotes a display circuit including an indicator, which receives the control signal 37 and displays on the indicator the relationship between the dynamic range of the output circuit 13 and the amplitude of the signal currently being output.

A control circuit 16 outputs control signals 33, 35, 36 and 37 in response to an instruction signal 31 from a keyboard or soft keys (not shown).

The display example of the display screen included in the display circuit 15 is shown in the second example.
It is shown in the figure and will be explained using it.

In FIG. 2a, 50 is a display surface included in the display circuit 15, such as a liquid crystal display, a plasma display panel, etc.
It is a display, electroluminescence, cathode ray tube, light emitting diode array, etc., and includes a waveform display section 51 for showing a waveform 52 at its center. In addition, soft keys 61 to 66 are shown at the bottom of the display surface 50 for various instructions such as repetition frequency (FRQ), amplitude (AMP), offset (OFS), and upper and lower limit values of the output waveform. Keys for displaying soft keys at a certain limit (LMT) or next candidate (NEXT) are lined up, and various setting values instructed here are displayed on the left side of the display screen 50. Instructions input from these soft keys 61 to 66 or keys on an operation panel (not shown) are applied to the control circuit 16 by an instruction signal 31.

On the left side of the waveform display section 51 is an indicator 54.
It is shown. The details of this are shown enlarged in FIG. 2b, where range "D" indicates the dynamic range of the output circuit 13, in which the signal has good linearity and is not distorted. The value of "D" is known in advance from the characteristics of the output circuit 13 and is stored in the control circuit 16.

Based on the instruction signal 31, the control circuit 16
Since it outputs control signals 33, 35 and 36,
At the same time as outputting these control signals, output terminal 2
Calculate the amplitude "S" of the output signal obtained by superimposing the offset obtained on 0, and taking into account the value of the offset,
A control signal 37 is outputted to the display circuit 15 to display the signal amplitude "S" 57 in a corresponding portion of the range "D" indicating the dynamic range.

In FIG. 2b, the hatched area at the top indicates the upper margin range (upper margin range) 55 in the dynamic range, and the hatched area at the bottom indicates the lower margin range in the dynamic range. Margin range (lower margin range)
It shows.

For example, if the value of the signal amplitude "S" is kept constant and the value of the offset is changed in the positive direction, the signal amplitude "S" 57 will shift upward, the upper margin range 55 will be reduced, and the lower margin range will be reduced. 56 is enlarged. If the offset value is further changed in the positive direction, the upper margin range 55 will finally disappear. In this state, distortion begins to occur in the upper part of the signal amplitude. Conversely, when the offset value is changed in the negative direction, the signal amplitude "S" 57 moves downward, and finally,
The lower margin range 56 disappears, and the lower part of the signal is
Distortion begins to occur.

If the value of the signal amplitude "S" 57 is increased, the range of "S" will expand up and down, and both the upper and lower margin ranges 55 and 56 will decrease,
When the margin range disappears, distortion begins to occur.

In FIG. 2, an example is shown in which the indicator 54 is shown on a part of the display surface 50 that displays waveforms and data. However, as is clear from the above explanation, the indicator 54 is displayed on the waveform display screen.
It is not necessary to indicate the offset value; for example, it can be displayed near the key for indicating the offset value by a light emitting diode array, a bar-shaped plasma display, a liquid crystal display, electroluminescence, etc. It is.

[Effects of the Invention] According to the present invention, it is possible to immediately know whether or not the amplitude of the output signal is within a dynamic range with good linearity.
There is no need to worry about exceeding the range, and there is no need to use an oscilloscope to monitor it, so it is extremely convenient for measurements and makes it possible to make accurate measurements efficiently. The effects of the invention are extremely large.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a display screen for explaining an example of the operation of the device shown in FIG. 10... Signal generation circuit, 12... Amplitude adjustment circuit, 13... Output circuit, 15... Display circuit, 16
... Control circuit, 20 ... Output terminal, 31 ... Instruction signal, 33, 35, 36, 37 ... Control signal, 4
1, 42...Signal waveform, 50...Display surface, 51...
... Waveform display section, 52 ... Waveform, 54 ... Indicator, 55 ... Upper margin range, 56 ... Lower margin range, 57 ... Signal amplitude.

Claims (1)

[Scope of Claims] 1. A signal generating means for generating a designated signal, an amplitude adjusting means for making the output of the signal generating means have a designated amplitude, and an output of the amplitude adjusting means having a commanded amplitude. an output means for superimposing and outputting a superimposed offset; a display means for displaying instructed information; and a control means for instructing the signal generation means, amplitude adjustment means, output means, and display means. In the signal generator, the display means displays the dynamic range of the output means, and displays the amplitude range of the signal output from the output means in correspondence with the dynamic range. Characteristic signal generator. 2. Claim 1, wherein the display means displays the dynamic range and the amplitude range of the signal within a display screen for displaying the waveform of the signal output by the output means. signal generator.