Norm Swanberg; Dome Resonators; San Diego, Ca; NSwanberg@msn.com; Tel 858-486=3308

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I have the 500 MSPS Eng Eval Board for the AD9434

MY TEST SET UP

I am injecting a CW, 600 MHZ signal from a calibrated signal source (Agilent 8657a) at -60 dBm and then again at -10 dBm. There is a 600 MHz, 40 MHz BW filter between the source and the ADC94343 Eval Brd.

I have a very low jitter 320 MHz source (Agilent 8657a) for the clock set to +10 dBm per the spec sheet reqmnts.

Signals are screen captures of the data.

The fundamental question I have is what are the correct setting so that the captured signals from the A to D are correct. The setting values make the captures VERY different.

The data sheet seems to indicate this board has a FIFO of 64 K making 65536 the correct length.

Please Confirm.

The AN-905 Ap note says ;“An Input Formatter must always follow the ADC Model Component if you want to pedrform processing within the canvas. The only exception to this rule is Logic Analysis. The Input Formatter takes the resolution of the ADC into account when moving data into the environment of VisualAnalog. For more information on setting up the Input Formatter, see the Input Formatter section.

Figure 48. ADC Model and Settings Form All Analog Devices models are LSB-justified and, therefore, the Alignment check box within the Input Formatter should be set to the native resolution of the model. The resolution on the Input Formatter should be set to the native resolution of the model as well. Note that the alignment setting is different when using the Input Formatter with the ADC Data Capture component. The number format should be set in accordance with the data format of the ADC model.”

I am not sure how this relates to the configurations I need to pick and this may be the fundamental problem.

OFFSET BINARY CAPTURES

If I set the input signal to -10 dBm and the Number Format to Offset Binary I get fundamental power -26.5 dBFS

If I change the input power to -60 dBm I get fundamental power =-77.1 dBFS…. a change of about 50 dB from the previous measurement. This makes sense.

However, the noise floor for a 12 bit A to D seems VERY low

TWO’S COMPLEMENT CAPTURES

If I do the same experiment with the 2’s complement I get

For Pin =-10 dBm I get Fund Power at 1.9dBFS (compressed)

For Pin =-20 dBm I get Fund Power at 2 dBFS (compressed) Higher?

For Pin =-40 dBm I get Fund Power at 0.6 dBFS

For Pin =-50 dBm I get Fund Power at -15.9 dBFS

And for Pin =-60 dBm I get fundamental power at -34.2 dBFS

The noise floors look kinda right but the tracking of captured dBFS does not

Since the board clock and data clock are not synched I use windowing

Additional questions

1. The graph capture screen has two feeds. On e for direct samples in the Time domain and the second for the processed FFT display. You are4 supposed to be able to toggle between the two for screen capture and for data export. I haven’t been able to figure out how to do this. Please advise. I think it is the Toggle Additional plot Icon, but not sure what data goes out on export.

2. I want to export the data to a text or word file but it seems to default to and Excel file. How do I fix this?

3. I would like some helpo figuring out how to write Paramters into the User Defined settings.

4. When I try to save these setting my Visual Anlaog program crashes!5. I would like to figure out how to save the FFT data into signal spectral density ( e.g. the

power spectral density of the noise floor. Or the Power spectral density of a modulated and NOT CW signal