Cirrus-logic AN44 Manuel d'utilisateur télécharger pdf

INTRODUCTION

The CDBCAPTURE system can be used to

collect data from embedded Analog to Digital

Converters (ADCs). Thus system performance of

the analog front end can be measured, analyzed

and quantified. By analyzing the measured

performance, noise sources can be identified,

isolated, and corrective actions taken. Here

CDBCAPTURE is used as an engineering tool,

reducing development time during system test

and integration. Another application could be

using CDBCAPTURE in production for testing

finished products and verifying system

performance.

CDBCAPTURE

The CAPTURE interface board is a development

tool that interfaces a Crystal Semiconductor

ADC to a PC compatible computer. Digital data

from the ADC is collected in a high speed

digital FIFO, then transmitted to the PC over a

serial COM port. Evaluation software is included

to analyze the data and demonstrate the ADC’s

performance. The entire system consists of a

CAPTURE interface board, serial cable, RS232

cable, and software.

The software included with the CDBCAPTURE

system quantifies static and dynamic

performance of ADC systems. Static testing

includes Histogramming and calculation of the

mean, standard deviation and variance. Dynamic

testing includes Fast Fourier Transforms and

analysis of the power spectrum. Here Signal to

Noise Ratio (SNR), Signal to Noise plus

Distortion (SINAD), Signal to Distortion Ratio

(SDR), and Signal to Peak Noise (SPN) figures

are calculated. Time domain plots are available

to visualize signals in the time domain and

confirm operation.

CDBCAPTURE WITH EMBEDDED ADCs

The CDBCAPTURE circuit board is designed to

directly interface with most Crystal

Semiconductor ADC evaluation boards. This

permits a quick and easy method to quantify and

verify the ADC’s performance. However, it is

often desirable to measure the ADC’s

performance in the actual system or to measure

the overall system performance. To collect data

from an embedded ADC, a special serial cable

needs to be designed. This cable incorporates the

digital interface circuitry which exists on the

evaluation board. This cable is connected to the

appropriate signals on the ADC.

To collect data from an embedded ADC, the

digital interface circuitry on the evaluation board

needs to be incorporated on a modified serial

FEB ’95

AN44REV2

Crystal Semiconductor Corporation

P.O. Box 17847, Austin, TX 78760

(512) 445-7222 FAX 445-7581

http://www.crystal.com

Application Note

USING THE CDBCAPTURE SYSTEM

WITH EMBEDDED A/D CONVERTERS

John Lis



Crystal Semiconductor Corporation 1996

AN44

1 2 3 4 5 6 7 8

Résumé du contenu

Page 1 - Application Note

INTRODUCTIONThe CDBCAPTURE system can be used tocollect data from embedded Analog to DigitalConverters (ADCs). Thus system performance ofthe analog fr

Page 2 - 2 AN44REV2

cable. Figure 1 is a block diagram illustratingthe process. On the top of Figure 1, theevaluation board CDBXXXX contains digitalinterface circuitry wh

Page 3

CS5508 EXAMPLEThe following example uses a CS5508 toillustrate the process of designing a modifiedserial cable. By examining the schematic for theCDB5

Page 4

Figure 4 shows how the hardware can beimplemented. The digital interface circuitry isbuilt upon a small circuit board. A ribbon cablewith a 10 circuit

Page 5

Figures 4, 5 and 6. The digital interface circuitryfor the CS5102A is show in Figure 5. Figure 6 is the way the digital circuitry isimplemented on the

Page 6 - of 1.59 counts or 218

Testing An Embedded ADCSystem performance can be measured byinterfacing the embedded ADC. The previoussections described the hardware modificationrequ

Page 7 - AN44REV2 7

CONCLUSIONThe CDBCAPTURE system is designed toeasily connect to most Crystal SemiconductorADC evaluation boards. Digital circuitry isincluded on the e

Page 8 - • Notes •

• Notes •Using The CDBCapture System with Embedded A/D Converters8 AN44REV2

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Cirrus-logic AN44 Manuel d'utilisateur

Naviguer en ligne ou télécharger Manuel d'utilisateur pour Matériel Cirrus-logic AN44. Cirrus Logic AN44 User Manual Manuel d'utilisatio

Résumé du contenu

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