JPS5975366A - Function generating device - Google Patents

Abstract

PURPOSE:To output with high accuracy a trigger signal to a prescribed position of a sweep waveform by storing a digital crest value of the sweep waveform, and comparing a data fetch pointer from a storage means with a prescribed trigger pointer. CONSTITUTION:A function generator 2 stores digital crest values X1-Xn of a sweep waveform provided at every data pitch DELTAt from an electronic computer 1, in a data memory 10. A DMA device 11 fetches the data x1-xn from the memory 10, sends them to a D/A converter 4 and also outputs successively fetch pointers 1-(n) of the data to a comparator 15. A controlling circuit 12 outputs a starting internal trigger signal ST of each converting period to the device 11 in accordance with a start command from the computer 1. A buffer 13 sends a pointer (i) to the comparator 15 in accordance with a command from the computer 1. The converter 14 converts the crest values x1-xn to analog, outputs them, and the comparator 15 outputs an external trigger signal TR when the signals 1-(n) and the pointer (i) coincide with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a function generator C1 that outputs a trigger signal at an arbitrary position of a sweep waveform.

[Technical background of the invention and its problems]

Conventionally, when generating a trigger signal at a predetermined position of the output waveform of a function generator, a function generator and a separate C2 frequency detection device are provided, and the output waveform is detected from the point where the output waveform crosses a reference value (for example, zero voltage) to the next point. The time taken to reach the crossing point was measured.

However, when the frequency of the output waveform of the function generator changes, the trigger signal cannot be output at the correct position.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a function generator that can accurately output a trigger signal at a predetermined position of a sweep waveform.

[Summary of the invention]

The present invention includes a data memory that stores the peak value of a sweep waveform given for each data pitch, and a D/A that sequentially retrieves the data pitch and C1 data from the data memory.
a DMA device that outputs a peak value signal externally f2 via a converter and sequentially outputs the data retrieval pointer;
Equipped with a comparator that compares the sequentially output pointers mentioned above with a preset trigger pointer and outputs a trigger signal to the outside when the two match, so that when reproducing the sweep waveform from the data memory, it can be used accurately at any position on the waveform. (This is a function generator that outputs two trigger signals.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG.

In FIG. 1 f2, 1 is an external electronic computer, and 2 is a function generator of the present invention.

The function generator 2 generates the digital peak value r of the sweep waveform given from the electronic computer 1 for each data pitch Δt.
l ” 3: a data memory 10 for storing n;
Data from the data memory 10 via the data bus,
21'1-3; Takes out data n and sends it to the D/A converter 14I-, and sequentially sends the data take-out pointers 1 to n to the comparator 15.
a control circuit 12 that outputs an internal trigger signal for startup for each conversion cycle to the DMA device 11 in response to a startup command from the computer 1;
A buffer 13 that temporarily stores a pointer l that generates an external trigger signal in response to a command from a digital peak value:
D/A converter I4 which converts T1'' and fn into analog signals and outputs them, compares the pointer signals 1 to n sequentially inputted from the DMA device 11 and the trigger pointer i inputted from buffer ■3, and finds that they match. and a comparator 15 that outputs an external trigger signal when this occurs.

Next, the operation of C2 in FIG. 1 will be explained using the time chart in FIG. 2.

In FIG. 2, Zjl -jcfl is data memory 1
It is an analog output corresponding to the data stored in pointer 0, and is taken out corresponding to pointers 1 to n via DMA II and the D/A converter 14 for each data pitch Δt by the activation trigger signal from the control circuit 12. be done.

When the pointers 1 to n become the trigger pointer 2 on the way, the trigger signal TR is outputted to the outside (-) at the same time as the analog output number x.

Next, FIG. 3 shows another embodiment of the present invention.

FIG. 3 shows a case where multiple timings for outputting trigger signals are specified, and the pointer memory 16 stores multiple pointers p1-P from the electronic computer 1 and stores them as DM.
They are sequentially read out via the A device 17 and compared with pointers 1 to n from the DMA device 11 in the comparator 15.

When the two match, external trigger signals are sequentially output.

By using the circuit shown in FIG. 3, the trigger signal can be output multiple times within one waveform.

FIG. 4 shows an example where the present invention is applied to control a vibration testing machine.

In FIG. 4 (2), when a specimen 8 is placed on a vibration table 7 and vibrated by a vibrator 9, the vibration condition is detected by an analog signal via a sensor 4.

This analog signal is converted into a digital value via an amplifier 5 and an A/1) converter 6, and read by the electronic computer 1.

The electronic computer 1 stores excitation waveform data in the function generator 2 for each data pitch Δt, and further stores a pointer corresponding to the designated timing in the function generator 2C.

When the computer 1 sends a start signal to the function generator 2, the function generator 2 converts the data stored in the td data memory into an analog value number and operates the vibrator 9 via the amplifier 3. When sent as a signal, C2, Lightning, and slave computer 11-) IJ sends a signal and commands to start measurement.

This controls the test operation of the vibration testing machine. [Effects of the Invention] As explained above, according to the present invention, the sweep waveform can be stored and reproduced, and the trigger can be triggered at any precise position in the waveform cycle. 0 which yields a function generator that outputs a signal

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a function generator according to the present invention, FIG. 2 is a time chart showing the operation of the present invention, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 4 is a diagram showing the configuration when the present invention is applied as a mini-vibration tester. buffer 14
D/A converter 15 Comparator 16 Pointer memory Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A data memory stores the peak value of the sweep waveform given for each data pitch, and data is sequentially extracted from the data memory for each data pitch and outputs a peak value signal to the outside via a D/A converter. A function generator characterized by comprising a DMA device that sequentially outputs takeout pointers, and a comparator that compares the sequentially output pointers with a preset trigger pointer and outputs a trigger signal to the outside when the two match. Device.