Should I sell my 54645D for a new Rigol?

[David Hess]

The 54622D has 1000 horizontal points, the "patented high resolution display, still beats many $20K scopes today. I'd like to find the patent on that BTW...

It sure does.  I was unaware of its high CRT horizontal resolution and may have to add this series to my list of old DSOs to watch for.  In my mind, LCD based DSOs are only now catching up to this level of display performance.  It is worth noting that a lot of old vector CRT DSOs has similar or better resolution in an even smaller screen size.  Vector CRTs have an advantage in this respect since their horizontal resolution is limited by deflection and not z-axis modulation bandwidth.

I did a cursory search for the patent but came up empty.  I wonder if HP licensed the patent from someone else.

[EGDima]

The 54622D has 1000 horizontal points, the "patented high resolution display, still beats many $20K scopes today. I'd like to find the patent on that BTW...

It sure does.  I was unaware of its high CRT horizontal resolution and may have to add this series to my list of old DSOs to watch for.  In my mind, LCD based DSOs are only now catching up to this level of display performance.  It is worth noting that a lot of old vector CRT DSOs has similar or better resolution in an even smaller screen size.  Vector CRTs have an advantage in this respect since their horizontal resolution is limited by deflection and not z-axis modulation bandwidth.

I did a cursory search for the patent but came up empty.  I wonder if HP licensed the patent from someone else.

But it's not a vector CRT screen right? It's interesting that the resolution for the waveform are is 255x1000 points, I wonder what shape the pixel has then, vertical resolution doesn't seem to be that high, although the display has 4:3 standard aspect ratio.

[David Hess]

The 54622D has 1000 horizontal points, the "patented high resolution display, still beats many $20K scopes today. I'd like to find the patent on that BTW...

It sure does.  I was unaware of its high CRT horizontal resolution and may have to add this series to my list of old DSOs to watch for.  In my mind, LCD based DSOs are only now catching up to this level of display performance.  It is worth noting that a lot of old vector CRT DSOs has similar or better resolution in an even smaller screen size.  Vector CRTs have an advantage in this respect since their horizontal resolution is limited by deflection and not z-axis modulation bandwidth.

I did a cursory search for the patent but came up empty.  I wonder if HP licensed the patent from someone else.

But it's not a vector CRT screen right? It's interesting that the resolution for the waveform are is 255x1000 points, I wonder what shape the pixel has then, vertical resolution doesn't seem to be that high, although the display has 4:3 standard aspect ratio.

It is a raster CRT so far as I know.  The pixel spacing is obviously not square but that is hardly uncommon with a raster CRT.

Some of the old DSOs which use vector CRTs are 1024 x 1024 on a 5x4 aspect ratio CRT which is only 5 inches diagonal so they predate the modern "retina" displays by decades.  Most are 512x1024 or 256x1024 though.

[edavid]

Some of the old DSOs which use vector CRTs are 1024 x 1024 on a 5x4 aspect ratio CRT which is only 5 inches diagonal so they predate the modern "retina" displays by decades.  Most are 512x1024 or 256x1024 though.

But what is the spot size of those CRTs?  I think real resolution in lines per inch is much less than the positioning resolution.

[David Hess]

Some of the old DSOs which use vector CRTs are 1024 x 1024 on a 5x4 aspect ratio CRT which is only 5 inches diagonal so they predate the modern "retina" displays by decades.  Most are 512x1024 or 256x1024 though.

But what is the spot size of those CRTs?  I think real resolution in lines per inch is much less than the positioning resolution.

Since these vector CRTs were originally designed for high bandwidth analog oscilloscopes, they have a smaller than normal spot size by virtue of their high acceleration voltages but you are right, their positioning resolution is greater than their line resolution.

I tested my lowest definition vector CRT which is 512x1024 and the spot size definitely yields better than 500 lines.  I have some others (faster CRTs with higher acceleration voltages) which would do better.