JPH0822341A - Arbitrary frequency generator - Google Patents

Abstract

(57) [Summary] [Purpose] To realize an arbitrary frequency generator that can capture time-frequency data and reproduce a waveform with that frequency information. A frequency information memory for storing time-frequency information and transmitting time-frequency data according to a designated address from a first address generator, and a second address generating address which changes corresponding to the output of the frequency information memory. Address generator, a waveform memory in which the waveform data is stored and the waveform data is read at a specified address from the second address generator, a DA converter for converting the output data of the waveform memory into an analog signal, and a frequency-time from the outside. A communication circuit for receiving information data by communication and a control arithmetic circuit having a function of writing the frequency-time information received via the communication circuit into the frequency information memory are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arbitrary waveform generator for generating an arbitrary signal, and more particularly to an arbitrary frequency generator capable of generating an arbitrary frequency, which takes in a frequency of an actual waveform and generates the frequency signal. It is about.

[0002]

2. Description of the Related Art Arbitrary waveform generators for sequentially reading out waveform data stored in a waveform memory and performing analog conversion to generate analog waveforms have been well known. FIG. 3 is an explanatory diagram of a system configuration when an actual waveform is captured by using this arbitrary waveform generator and the waveform is reproduced.
First, the actual waveform is captured by the digital oscilloscope 100 (may be a digitizer). The digital oscilloscope or digitizer includes an analog / digital converter (hereinafter, analog / digital conversion is referred to as AD conversion) and a memory, and voltage-time data of an actual waveform can be measured and stored in the memory. The data stored in this memory is transferred (downloaded) to the arbitrary waveform generator 200 and temporarily stored in the waveform memory of the arbitrary waveform generator. After that, the waveform data is read from the waveform memory and the reproduced waveform is output.

[0003]

However, this method has the following problems. In other words, the time-voltage information captured by the digital oscilloscope is captured in the memory of the arbitrary waveform generator and played back. However, a signal whose frequency fluctuates as shown in FIG. 4 (FIG. 4A shows a real waveform, and FIG. 4B shows a change in the frequency of the real waveform), for example, a rotation signal waveform. In the above, there is a drawback that many sampling points are required in order to take in and reproduce data only by the voltage-time relationship, therefore an ultra-long memory is required and a processing time such as transfer is also required.

In view of the above, an object of the present invention is to capture (download) time-frequency (or time-cycle) data measured by a frequency counter or a time interval counter for an actual signal whose frequency fluctuates. ), It is intended to realize an arbitrary frequency generator capable of reproducing a waveform having the frequency information.

[0005]

In order to achieve such an object, according to the present invention, an address is designated by a first address generator which stores time-frequency information and generates an address signal which changes at a predetermined rate. Then, the frequency information memory configured to send the contents stored at the designated address and the output of the frequency information memory are received as frequency data, and an address signal that changes corresponding to this frequency data is generated. A second address generator for storing waveform data, and a waveform memory configured to read waveform data stored at the address when the address is designated from the second address generator, and the waveform memory A DA converter that converts the output data of the analog to analog and the time-frequency information are stored, and are converted at a predetermined rate. First for generating an address signal for
When an address is specified from the address generator of
A frequency information memory configured to send the contents stored in the designated address as frequency data of the second address generator, and a communication circuit capable of receiving frequency-time information data from the outside by communication. And a control arithmetic circuit having a function of writing the frequency-time information received through the communication circuit into the frequency information memory.

[0006]

The waveform data is read from the waveform memory by the address generated from the second address generator, and DA
Output as an analog waveform through the converter. The frequency of the output analog waveform changes according to the frequency data given to the second address generator. The frequency data is time-frequency information stored in the frequency information memory, and in the present invention, the time-frequency information can be loaded into the frequency information memory through the communication circuit. By writing the time-frequency information in the frequency information memory and storing the basic waveform in the waveform memory, the DA converter can reproduce the waveform having the frequency information according to the time-frequency information.

[0007]

The present invention will be described in detail below with reference to the drawings.
FIG. 1 is a configuration diagram of a main part showing an embodiment of an arbitrary frequency generator according to the present invention. In the figure, 10 is a first address generator, 20 is a frequency information memory, 30 is a second address generator, 40 is a waveform memory, 50 is a digital-analog converter (hereinafter digital-analog conversion is referred to as DA conversion), 60 Is a control arithmetic circuit, and 70 is a communication circuit.

The first address generator 10 generates an address in synchronization with a reference clock (a clock generator is not shown). In addition,
The internal configurations of the first address generator 10 and the second address generator 30 are the same. The first address generator 10 comprises an adder 11 and a latch 12. The latch 12 latches and outputs the output of the adder 11 for each clock pulse input. The adder 11 adds the output of the latch 12 and the total time N. Latch 1
The output of 2 (data increasing by N in this case) becomes an address for the frequency information memory 20.

The frequency information memory 20 is a memory for storing frequency-time information, that is, frequency sweep data. This frequency sweep data is added to the second address generator 30 as frequency data M. The second address generator 30 is M for the waveform memory 40.
Addresses that change in steps are output. A desired basic waveform is stored in the waveform memory 40, and the waveform data is read by addressing the second address generator 30. The read waveform data is analog-converted by the DA converter 50.

The frequency of the output waveform of the DA converter 50 is the second
Corresponding to the frequency data M given to the address generator 30 of. If M doubles, the frequency doubles,
If M is tripled, the frequency is also tripled. The value of M is the time-frequency data stored in the frequency information memory 20, and therefore the frequency of the output waveform output from the DA converter 50 is the frequency according to the time-frequency data.

The control arithmetic circuit 60 has a function of writing an external signal input via the communication circuit 70 into the frequency information memory 20. Also, the waveform data can be written in the waveform memory 40. The communication circuit 70 is an interface circuit for downloading a signal from an external frequency counter, time interval counter, or the like (both not shown).

The operation in such a configuration will be described below with reference to the configuration diagram of the system relating to signal transfer and reproduction shown in FIG. The frequency is measured by a time interval counter or a frequency counter 300 having a memory function for a sine wave having a constant amplitude and the frequency is changed, and the frequency data is measured and the arbitrary frequency generator 40 of the present invention is used.
Download to 0.

The control arithmetic circuit 60 writes the frequency data (time-frequency data) received via the communication circuit 70 into the frequency information memory 20. In this case, the number of data is much smaller than that in the case of faithfully sampling the actual waveform of the voltage change, and the memory length is also small. The basic waveform of the sine wave is written in the waveform memory 40 in advance.

When reproducing a waveform similar to the actual waveform, the first address generator 10 is activated to generate an address for the frequency information memory 20. At the same time, the second address generator 30 is also activated to generate an address for the waveform memory 40. Frequency data according to the frequency change of the actual waveform is output from the frequency information memory 20, and the frequency data M is output to the second address generator 30.
Added as. As a result, the waveform read from the waveform memory 40 is a waveform having a frequency that changes according to the frequency data read from the frequency information memory 20, in other words, a waveform that follows a frequency change of an actual waveform.

The present invention has not only the function of an arbitrary frequency generator but also the function of an arbitrary waveform generator for generating an arbitrary waveform. That is, it is set so that constant frequency data M is added to the second address generator 30 from the frequency information memory 20.
An arbitrary waveform can be generated by appropriately changing the waveform stored in 0. It is also possible to download the waveform data from an external digital oscilloscope, write it in the waveform memory 40, and reproduce it. In any case, the same function as that of the conventional arbitrary waveform generator can be exerted.

Further, the present invention is not limited to the embodiments, and the structure can be appropriately changed without departing from the object of the present invention.

[0017]

As described above, according to the present invention, in addition to downloading waveform data from a conventional digital oscilloscope, external frequency-time information is downloaded to a frequency information memory that stores frequency-time information. By doing so, it is possible to easily generate a frequency sweep signal which could not be generated due to the limitation of the memory.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram showing an embodiment of an arbitrary frequency generator according to the present invention.

FIG. 2 is a diagram illustrating the configuration of a system using the arbitrary frequency generator of the present invention.

FIG. 3 is an explanatory diagram of a system configuration using a conventional arbitrary waveform generator.

FIG. 4 is a characteristic diagram of an actual waveform.

[Explanation of symbols]

 10 First Address Generator 11,31 Adder 12,32 Latch 20 Frequency Information Memory 30 Second Address Generator 40 Waveform Memory 50 DA Converter 60 Control Arithmetic Circuit 70 Communication Circuit

Claims (1)

[Claims] 1. When an address is designated by a first address generator which stores time-frequency information and generates an address signal which changes at a predetermined rate, the contents stored at the designated address are transmitted. A configured frequency information memory, a second address generator that receives an output of the frequency information memory as frequency data and generates an address signal that changes corresponding to the frequency data, and waveform data is stored in the second address generator. The waveform memory configured to read the waveform data stored at the address when the address is specified by the address generator, the DA converter for converting the output data of the waveform memory into an analog signal, and the external frequency A communication circuit capable of receiving time information data through communication, and a communication circuit The control-arithmetic circuit having a function of writing the received frequency-time information in the frequency information memory is provided, the time-frequency information fetched by communication from the outside is written in the frequency information memory, and the time-frequency information is obtained from the DA converter. An arbitrary frequency generator characterized in that a waveform based on is output.