Circuit Note

CN-0582

analog.com

Rev. A | 9 of 10

9. Click the start button to begin capturing and viewing time and

frequency domain data from the ADC.

ANALOG INPUT TESTING RESULTS

For input channel accuracy, a precision audio analyzer is used

as input source of which percentage error must be less than 1%

at any amplitude and frequency. Table 5 shows the measured

values for four channels displayed in GUI corresponding to the test

parameters from the equipment.

At amplitudes less than 100 mVp-p, the maximum error is ±2

mVp-p; while at above 100 mVp-p, the average error is less than

1%.

Table 5. Analog Input Measurements

DC BIAS = 6 V

Test Amplitude (mVp-p) at Gain = 1

10

100

1000

5000

10000

Test

Frequency

(kHz)

0.1

10.96

100.60

1000.51

4996.04

9992.53

1

10.96

100.93

1000.70

4996.11

9993.93

5

10.93

100.74

999.68

4991.07

9984.00

10

10.93

100.48

996.35

4975.71

9953.88

25

10.80

98.46

975.81

4871.66

9745.64

ANALOG OUTPUT TESTING RESULTS

To assess the signal generator, the output waveform is measured

using an oscilloscope. Similar with the input channels, the average

error must be less than 1% at any amplitude and frequency setting.

Table 6 shows the programmed frequency and amplitude of a

sinusoidal waveform captured on the oscilloscope, resulting in an

error within 1%.

Table 6. Analog Output Measurements

Signal Generation

(Full Bandwidth)

Test Amplitude (mVp-p)

100

500

1000

2000

3000

3500

7000

Test

Frequency

(kHz)

0.1

100.2 500.6 1001

2000.6

2998

3492

6976

1

100.2 499.7 1004

1994

3004

3500

6988

5

100

500.5 999.8

2000

2998

3502

6983

10

100.5 502.4 1004

2007

3010

3520

6999

25

100.1 504.7 1008

2014

3022

3526

6970

50

102.5

512

1023

2042

3062

3285

6510

Figure 15. Signal Output with 3.5 Vp-p, 5 kHz Settings