JPS6143883B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arbitrary waveform generation method for generating an arbitrary analog waveform.

There are various methods for generating arbitrary waveforms. For example, one method is to store generated data to be generated in advance at a predetermined address in memory in the order of generation, access the memory sequentially, read out the generated data, and generate an arbitrary analog waveform as an analog value via a DA converter. It is.

In this conventional example, as shown in Fig. 1, there is a memory MEM that stores waveform data in the order of generation, a DA converter DAC that sequentially converts the waveform data read from the memory into analog values, and a DA converter DAC that is given command information and stores the memory in a predetermined order. A memory controller MCOT is provided for access. That is,
When the size of the memory MEM is 1024 words and a waveform as shown in Fig. 2 is to be generated, the waveform is divided at predetermined time intervals in advance and the voltage value at each time is sequentially stored in the memory as waveform data at the address and time. When generating the analog waveform, the command information is decoded by the controller MCOT and the memory is sequentially accessed at regular intervals starting from the first address where the data of the waveform is stored.
- An arbitrary waveform is generated by reading it to the A converter DAC and converting it to an analog value using the DA converter.

However, in such conventional methods, even when a constant voltage continues for a long time, the time must be divided and the constant voltage at each time must be stored as waveform data, and the same waveform is repeated. However, even if the voltage value at each time is different, it is necessary to store the voltage value at each time in the memory. For this reason, the conventional arbitrary waveform generation method requires an extremely large amount of memory, causing an increase in costs. Furthermore, for any waveform, the voltage value at each time must be stored in a memory, making it troublesome to create and store data. However, the present invention provides a new arbitrary waveform generation method that eliminates such conventional drawbacks.The purpose of this invention is to provide a new arbitrary waveform generation method that eliminates such conventional drawbacks. a memory comprising control data including information indicating the generation time, in which information stored in a storage area at the same address is assigned a different address for each waveform generation data, and a memory to which the waveform generation data is supplied; a D-A converter that converts the data into an analog voltage, and a controller that gives an address to the memory and sequentially reads out the information to generate an arbitrary waveform. The control data is supplied to the D-A converter and is also input to the controller, and the controller controls the read time until the next information is read based on the input control data. This is achieved using an arbitrary waveform generation method.

That is, information at a predetermined address stored in the memory is read out, and based on this information, the time to read the next address is determined by referring to the contents of the bit indicating the hold time from the control bit. The data bits sent to the output of the DA converter may be any type of DA converter that maintains the same state for a certain period of time.

With this configuration, when outputting the waveform shown in Figure 2 explained above, the same state will continue for a certain period of time, especially at the peak part of the waveform, but this part can be specified by the control bit. In the end, you only need one piece of data for each peak.

Therefore, the memory capacity can be reduced compared to the conventional method.

In this case, although the waveform in FIG. 2 does not maintain the same state very much, it is possible to save a lot of money if the output is a rectangular wave or the like.

Also, when a certain value continues alternately for a certain period of time, such as a square wave, if you use a subroutine command and cyclically read the data at multiple addresses required for one cycle of the waveform, you can set the hold time as well as the previous hold time setting. You can dramatically save memory.

Hereinafter, the present invention will be explained in detail with reference to the drawings.
FIG. 3 shows the format of information according to the present invention to be stored in the memory. One word consists of 16 bits, and 0 to 2 bits indicate the hold time.
3 to 4 bits indicate instructions such as branch instructions, subroutine instructions, external control instructions, etc., and 5 to 15 bits indicate generated data.
From now on, bits 0 to 4 will be used as control bits, and bits 5 and 5 will be used as control bits.
~15 bits are called data bits.

However, since the hold time is designated using a 3-bit configuration, eight (=2 ³ ) types of time can be designated.

Also, if the content of the 3rd to 4th bits is “01”, it is a branch instruction; if it is “10”, it is a subroutine instruction;
If it is "11", it is considered to be an external control command.
Now, the hold time command is a command to hold the output voltage of the DA converter constant for a specified time, and with this command, it is not possible to divide the same data over the necessary time and store it in the address corresponding to each time as in the conventional method. This makes it unnecessary, allowing memory capacity to be saved.

A branch instruction is an instruction to read waveform data from the next address where the branch instruction is stored, that is, the address indicated by the data bits of the address to be read next. It becomes easy to make changes such as deleting part of the existing waveform or redrawing it, and it is also possible to save memory.

The subroutine instruction is an instruction that regards the contents of the data bits at the next address as the start address of the subroutine, and if there is return information in the control bits within the subroutine, the program returns to the original address of the main routine.

As a result, repetitive waveforms can be efficiently generated at fixed time intervals with a small amount of memory.

FIG. 4 shows an example of an arbitrary waveform generator according to the present invention, where 1 is a memory controller, for example, composed of a microprocessor, and line 1 is an input line for inputting information read from the memory to the controller 1. Other symbols indicate the same parts as in FIG.

However, the microprocessor 1 performs processing based on a pre-stored program according to the contents of the control bits in the read data, and performs the hold time control, branch control, and subroutine control.

Here, the memory is simply configured as shown in Figure 3.
The operation of MEM and memory controller 1 will be explained.

When a designation of a generated waveform is input to the memory control 1 from the outside as shown by an arrow in order to generate an arbitrary waveform, a leading address for outputting the designated waveform is designated based on this command.

This starting address may be stored in the memory controller 1 for the types of waveforms that can be generated.

In this way, specify the starting address and store the memory
When the first address is read from the MEM, the information corresponding to data bits of this read information is output to the DA converter DAC, and based on these bits, it is converted into analog data to output a predetermined waveform. and output it.

On the other hand, the remaining control bits are input to the memory controller 1 via the signal line 1, and set the address to be read next and the time for the next read.

That is, as explained earlier, this control bit sets the hold time with the 0th to 2nd bits,
Branch and subroutine control are performed using 3 to 4 bits. Furthermore, the branch/subroutine instructions are the same as those of programs for general electronic computers, and detailed operations will be omitted.

Thus, according to the present invention, it is possible to provide an arbitrary waveform generator that can reduce the memory capacity, has a simple method of storing data in the memory, is inexpensive, and has good operability.

[Brief explanation of the drawing]

FIG. 1 shows a conventional arbitrary waveform generator, FIG. 2 shows an arbitrary waveform for explaining the conventional method, FIG. 3 shows a format of stored information according to the present invention, and FIG. 4 shows an arbitrary waveform generator according to the present invention. It is. In the figure, 1 is a memory controller, MEM is a memory, and DAC is a DA converter.

Claims (1)

[Scope of Claims] 1. A waveform generation data indicating a value at a predetermined location of a waveform to be generated and control data including at least information indicating the generation time of the broken waveform generation data, and stored in a storage area at the same address. a memory in which different addresses are assigned and stored for each waveform generation data; a D-A converter to which the waveform generation data is given and converts it into an analog voltage; a controller that sequentially reads data to generate an arbitrary waveform, and provides data for waveform generation among the information read from the memory to the D-A converter;
An arbitrary waveform generation system characterized in that control data is input to the controller, and the controller controls the readout time until the next information is read based on the input control data.