JPH0284818A - A/d conversion circuit - Google Patents

Abstract

PURPOSE:To directly obtain an arbitrary A/D conversion value corresponding to an analog value by providing an address decoder and a memory, and setting a conversion value corresponding to the analog value on the memory in advance. CONSTITUTION:The conversion value corresponding to an analog input value is set on the memory 7A before A/D conversion is performed. For example, when the output code of an A/D converter 3 is a binary code and a binary coded decimal(BCD) code is desired to obtain as digital output 8A, the BCD code is set on a corresponding address on the memory 7A in advance. As a result, the digital output 8A can be obtained directly against analog input as the value of desired code format, which eliminate necessity to perform the conversion of an A/D-converted value again. Therefore, it is possible to efficiently perform the A/D conversion.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a circuit for digitizing an analog signal (A/D
Humbata).

[Conventional technology]

FIG. 3 is a block diagram of a conventional A/D converter. 1 is an analog input, 2 is a sample hold circuit, 3 is an A/D humbverter body, and 4 is a digital output of the A/D conversion result.

In conventional A/D:2 inverters, the output code format of the digital conversion value includes binary, offset binary, two's complement code, binary coded decimal (BCD), etc.; It is determined by the D converter 3 itself, and generally a binary output format is often used in which the digital output increases by 1 in proportion to the analog input. The resulting binary output was then converted into numerical values according to each purpose.

In other words, in a conventional A/D converter, the value is first converted into a value in a binary format or the like, and then the result is further converted into a food format or numerical value according to the purpose.

[Problem to be solved by the invention]

In the conventional A/D converter described above, the code format of the digital output of the conversion result can only obtain a value in a code format predetermined by the A/D converter, and the code format may not match the intended code format. In the case of different values, it was necessary to further convert the result converted by the A/D converter into a value in the target code format. Therefore, in order to digitize an analog signal, there is a drawback that the digital value must be further converted after being digitized once.

[Means to solve the problem]

The A/D converter of the present invention includes, in addition to a conventional A/D converter, an address decoder for decoding the output code of the A/D converter, and a memory referenced by the address decoder.

Therefore, by setting the converted value for the analog value in the memory in advance, it is possible to directly obtain any converted value corresponding to the analog value.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which the same reference numerals as in FIG. The output of the address decoder 5A, 7A is the memory accessed by the address selection line, and 8A is the output value of the memory 7A selected by the address selection line 6A. Before performing A/D conversion, set the conversion value corresponding to the analog input value in the memory 7A.
If the output code of the converter body 3 is a binary code, and you want to obtain a BCD code as the digital output 8A, write the BCD code on the corresponding address on the memory in advance.
:L-code is set.

In this way, the digital output 8A for the analog input is directly obtained as a value in the code format suitable for the purpose, and the A/
There is no need to convert the D-converted value again. Note that the conversion values may be set in the memory 7 in advance as a ROM according to the purpose of use, or may be set in the RAM before starting the conversion. . In FIG. 1, it is assumed that the memory is preset as a ROM.

FIG. 2 is a block diagram showing a second embodiment of the invention. The same reference numerals as in FIG. 1 indicate the same or corresponding parts. IB
, 2B, 3B, and 4B are analog inputs, 5B is a multiplexer that selects one input from analog inputs IB, 2B, 3B, and 4B, 8B is a control unit that controls multiplexer 5B, and 9B is a constant depending on the input signal. This is the constant part that generates .

Now, assume that the A/D converter body 3 is an 8-bit A/D converter, and the address decoder 5A is a 16-bit door address decoder. The A/D conversion result of the A/D converter 3 is input to the lower side of the 16-bit address decoder 5A as well as input signals IB and 2B.

The output of a constant generator 9B that generates an 8-bit constant according to 3B and 4B is input to the upper side of the address decoder 5A. For example, assume that address input IB is currently selected. At this time, if the constant generator 9B outputs IOH,
The A/D conversion result is determined according to the output of the A/D converter 3.
The memory value of the address where the upper 8 bits are 10 bits and the lower 8 bits are the converted value can be obtained as a digital output 8A.

Next, the analog input switches to 2B, and the constant generator 9B
outputs 20H, the conversion result is that the upper 8 bits are 20H.
The memory value of the address whose lower 8 bits of H1 are converted values can be obtained as a digital output 8A. That is,
Even if the analog input value is the same value and the conversion result of the A/D converter 3 is the same, by switching the upper address, it is possible to obtain the combustion result of a different hood type.

〔Effect of the invention〕

As explained above, the present invention allows the data format to be set in memory in advance.
The value of the target data format can be arbitrarily selected, and there is no need to convert the obtained conversion result once again to obtain the target data format, resulting in efficient A/D conversion. can be done.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing a second embodiment of the invention, and FIG. 3 is a block diagram of a conventional A/D converter. 1, IB, 2B, 3B, 4B...analog input, 2...sample hold circuit, 3...
・A/D converter main body, 4... Conversion output of A/D converter main body, 5A... Address decoder, 5B... Multiplexer, 6A...
・Address selection line, 7A...Memory, 8A...
...A/D conversion result output, 8B...multiplexer control section, 9B...constant generation section. Agent Patent Attorney Shinkamenme Uchihara

Claims (1)

[Claims] It has an A/D converter and a memory that receives the value of the conversion result of the A/D converter as an address input, and sets the value preset in the memory corresponding to the address as the value of the output of the A/D conversion. An A/D conversion circuit characterized by: