Hi Marco,

Yes, you are right, if the first converter is not linear because it is damaged, it will distort the test of the log detector.

A solution would be to input a signal at 321.4MHz to the A9J4 module, but I do not think it is worth doing the test given the results.

Your filters are correct, just that I notice that the amplitude is about 4 to 5dB higher than on my 8591A for the same test...but on my 8595E, I have the same behavior as your 8591E

The image showing the 5MHz filter having a level of almost 15dB higher than normal during the SELFCAL, I did not observe this behavior on my 8591A, but on my 8595E, which is in excellent condition, we see it very well during this calibration...so this behavior would be normal for the E version.

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The problem for the HPGL file comes from the data received by the rs-232 link. Your rs-232 utility did not retain the ascii code 03, which is the control signal ending a text label. Without this termination, your file will be unreadable. The LB characters are the beginning of a label, and 03 is the termination, which I added manually to your file, and this for all the LBs encountered.

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I asked a friend if he had a Spectrum of the 8590 series with rs-232 option, I could then modify my program and send it to you, I will know tomorrow.

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But today, I will do a test by rs-232 link on another instrument for an HPGL image capture, I will see the behavior.

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Yves

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