KR20000007221A - Digital-analog converter test device - Google Patents

Abstract

PURPOSE: A digital-analog converter test device is provided to enhance easily the resolution of a test device and upgrade it with ease by improving the sampling speed of an analog-digital converter. CONSTITUTION: The digital-analog converter test device comprises; a clock pulse generating part(10) to generate the 1st clock pulse(DA-CLK) and the 2nd clock pulse of which cycle is 1/n of that of the 1st clock pulse(AD CLK); a digital-analog converting part(20) to convert inputted N bit digital words into analog signals in response to the 1st clock pulse(DA CLK); an analog-digital converting part(40) to output N+2 bit digital words by digital converting the analog signal provided from the digital-analog converting part(10) by the 2nd clock pulse(AD CLK) cycle.

Description

Digital-to-analog converter test device

The present invention relates to a digital-analog converter test apparatus, and more particularly, to a digital-analog converter test apparatus capable of increasing resolution of a test apparatus by timing control.

As digital processing technology has recently replaced conventional analog processing technology, analog-to-digital converters convert analog real-world physical quantities into digital signals represented by binary numbers, and vice versa. The technology of the digital-to-analog converter has been developed in the direction of high speed and high resolution, and is applied to various fields.

Typically, an analog-to-digital converter is used as a test device to test the operating characteristics of the digital-to-analog converter. According to the rationale, at least n + 2 bits are required to test an n-bit digital-to-analog converter. There is a need for an analog-to-digital converter with resolution. Here, the resolution refers to the resolution when viewed based on the actually measured data, rather than simply the resolution of the bit concept. For example, to measure a 10-bit 20 MHz digital-to-analog converter, a 12-bit 20 MHz analog-to-digital converter or a 10-bit 80 MHz (= 20 MHz × 2 ² ) analog-to-digital converter is required. In other words, the input analog signal from the digital-analog converter is converted into an analog-to-digital converter having a sampling rate of 4 x Fs to test the digital-to-analog converter (DA converter) in which the output signal changes in units of T = 1 / Fs. Testing allows you to test even if the number of bits in the digital-to-analog converter and the analog-to-digital converter is the same.

However, it is difficult to have an analog-to-analog converter that satisfies the above conditions in actual conditions, and a new solution that can use the semiconductor automatic test equipment (ATE) that cannot be upgraded is needed. .

An object of the present invention is to provide a digital-analog converter test apparatus that can easily increase the resolution of the device of the test device by using the timing control.

In order to achieve the object of the present invention, the test apparatus of the present invention includes a clock pulse generator for generating a first clock pulse and a second clock pulse having a 1 / n period of the first clock pulse; A digital-to-analog converter for converting an input N-bit digital word into an analog signal in response to the first clock pulse; And an analog-to-digital converter for digitally converting an analog signal from the digital-to-analog converter according to the period of the second clock pulse, thereby outputting a digital word of at least N + 2 bits.

1 is a block diagram for explaining a digital-to-analog converter test apparatus according to the present invention.

2 is a diagram for explaining sampling using timing control of an analog-to-digital converter according to the present invention;

* Explanation of symbols for the main parts of the drawings

10; A clock pulse generator 20; Digital-to-analog converter

40; Analog-to-digital converter

Hereinafter, the technology of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating a digital-to-analog converter test apparatus according to the present invention. As shown in FIG. 1, a second clock having a 1 / n period of a first clock pulse DA_CLK and a first clock pulse DA_CLK is illustrated. A clock pulse generator 10 for generating a clock pulse AD_CLK, a digital-analog converter 20 for converting a digital word of input N bits into an analog signal in response to the first clock pulse DA_CLK, and It consists of an analog-to-digital converter 40 which outputs a digital word of at least N + 2 bits by digitally converting an analog signal provided from the digital-to-analog converter 10 according to the period of two clock pulses AD_CLK. .

An operation of the embodiment of the present invention configured as described above will be described with reference to FIG. 2.

The first embodiment of the present invention uses a timing control of the analog-to-digital converter, which is a test apparatus, so that the clock pulse generator 10 is fixed to make the sampling rate of the analog-to-digital converter four times faster than the digital-to-analog converter. The second clock pulse AD_CLK having a quarter cycle with respect to the first clock pulse DA_CLK and the fixed first clock pulse DA_CLK is generated, and the digital clock generator generates the fixed first clock pulse DA_CLK. At 20, the second clock pulses AD_CLK are provided to the analog-digital converter 40, respectively.

Then, the digital-analog generator 20 receives the fixed first clock pulse DA_CLK provided by the clock pulse generator 10, as shown in FIG. Analog sampling is performed in accordance with the cycle of (1), which is converted into an analog signal and outputted.

Next, as shown in FIG. 2, the analog-to-digital converter 40 provides a second clock pulse AD_CLK (which provides the analog signal from the digital-analog generator 20 to the clock pulse generator 10). Sampling is performed according to the period 2). Four sampling operations are performed within the period of the fixed first clock pulse DA_CLK 1. Next, the analog-to-digital converter 40 quantizes the sampling signal to convert it into a binary number of N + 2 bits, which is a digital word.

Therefore, the digital-analog converter, which is a test device for the digital-analog converter, increases the sampling rate by four times by the timing control of the clock pulse generator 10, thereby satisfying the required resolution of N + 2 bits.

The second embodiment of the present invention utilizes the timing control of a digital-analog converter as a test apparatus.

According to the second embodiment of the present invention, the clock pulse generator 10 provides a second clock pulse AD_CLK fixed to the analog-to-digital converter 40, and provides a second clock pulse to the digital-analog generator 20. A first clock pulse DA_CLK having a period of four times the clock pulse AD_CLK is provided. Then, the digital-analog converter 20 performs analog conversion on the N-bit input digital word according to the period of the first clock pulse DA_CLK.

In this way, the sampling rate of the analog-to-digital converter 40 is fixed even if the timing of the digital-to-analog converter 20 that performs the analog conversion on the N-bit input digital word after fixing the second clock pulse AD_CLK is controlled. The same effect can be obtained by increasing 4 times.

Therefore, in the present invention, by increasing the sampling rate of the analog-to-digital converter which is a test device by using the timing control, the resolution of the test device can be easily increased, and the test device can be easily upgraded.

Claims (2)

A clock pulse generator for generating a second clock pulse having a first clock pulse and a 1 / n period of the first clock pulse; A digital-to-analog converter for converting an input N-bit digital word into an analog signal in response to the first clock pulse; And And an analog-to-digital converter for outputting a digital word of at least N + 2 bits by sampling and digitally converting an analog signal from the digital-to-analog converter according to the period of the second clock pulse. Analog converter test device. The clock pulse generator of claim 1, wherein the clock pulse generator comprises: And applying a second clock pulse fixed to the analog-digital converter and providing a first clock pulse having a period of 4n of the fixed second clock pulse to the digital analog-digital converter. -Analog converter test device.