ADC-207

®

®

0

1

2

3

4

5

6

7

8

9

10

FREQUENCY (MHz)

70

65

60

55

50

45

40

35

30

25

20

15

10

5

0

–5

–10

69.2

27.3

SAMPLE PULSE WIDTH = 25ns

4MHz FUNDAMENTAL

Figure 5. Beat Frequency Test at 20MHz

Figure 6. 10MHz Envelope Test

FFT TEST

This test actually produces an amplitude versus frequency graph (Figure 7) which indicates harmonic distortion and signal-to-noise

ratio. The theoretical rms signal-to-noise ration for a 7-bit converter is +43.8dB.

Figure 7. FFT Test Using the ADC-207

0

1

2

3

4

5

6

7

8

9

10

70

65

60

55

50

45

40

35

30

25

20

15

10

0

–5

–10

SAMPLE PULSE = 25ns

69.2

27.3

4MHz FUNDAMENTAL

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

NUMBER OF SAMPLES (X10 )

3

OUTPUT

CODES

120

110

100

90

80

70

60

50

40

30

20

10

0

OUTPUT

CODES

120

110

100

90

80

70

60

50

40

30

20

10

0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

NUMBER OF SAMPLES(X10 )

3