X-Y Mode Rigol DS1102D

[GerryR]

I've attached a couple of pictures from an analog scope and the Rigol DS1102D in X-Y Mode.  I was doing some performance checks on a sweep generator w/ markers that require using a scope in X-Y mode.  A brief description of the setup involves taking the RF output into a demodulator and sending the demodulated output back into the generator's demod input.  The X and Y outputs of the generator are then fed to the 'scope.

The first picture is the analog scope (40 MHz Kenwood) with the markers (1MHz) turned on; no problems with the display.  I decided to try it on the Rigol.

Second picture is the Rigol.  At 1 Msample the display is basically useless.  You can slow the sample rate down to get a more consistent display, but it is still useless as it is just a maze of dots without much detail.

Third picture is the Rigol with persistance on infinite (only two choices, off or infinite)  the display is somewhat useful because the 'scope "fills in the blanks" so-to-speak, but not at all what I was expecting.

Does anyone know if I am doing something wrong or is this the nature of the beast.  I tried some Lissajous patterns and basically the same maze of dots, a terrible display except on the simplest of patterns.


 

[wraper]

DSO generally suck at X-Y, especially older/cheap models with low capture rate/ high dead-time, not to be confused with sample rate.

[GerryR]

So, which of the "more expensive" digital 'scopes could do this in "analog fashion?"