test equipment / Re: Z80 / Z84C Swap (Doh!)

The videos below are from 2009 so are now 6 years old, so about the same age as windows/7. I don't know of any modern USB scope that does equivalent time sampling. Memory Depth isn't so important as USB2 means you can shift the data pretty quickly into the PC. I also note he says proudly he doesn?t have a PC in is lab. I have several and they are really useful for many things. In 2009 I probably didn't, but these days they server as audio signal generators, audio frequency counters, and Audio oscilloscopes. with a DVB memory stick inserted they provide low cost, reasonable quality spectrum analysis. As for displaying the scope output how many scopes have a 14" screen. Those with a reasonable cost all have smaller screens where 8-bit sampling is probably OK. Note the Rigol he proudly trumpets has a 5.7" display. Yuk!. I also have recording 3.5 digit DVM with a USB interface. Good for recording data over short periods.... As he says for us with higher speed devices you probably want a 20Mhz displayable bandwidth, so I would say 80mhz sampling Minimum, he says 200Mhz, but for older vintage stuff you are seldom going to be going that fast. I own a DSO5200 as mentioned in the videos and its great, but the only time I have used its full abilities was to test a 0-30Mhz Direct Digital Synthesis frequency generator I built. I actually recently went and bought a 6022 as well. At the price I just don't worry about it, I throw it in the laptop bag and away I go. Well 12-bit is, imho a total waste of money for Computer Restoration or really most work. That?s equivalent to about 250 microvolts on a 0v to 1volt signal. I could see an argument for 10-bit which is about 1 millivolt on a 0v to 1volt signal, but that?s the most you can display on a 1168x1024 screen and even then you won't fit it all in as you will have some borders. (Double those figures for symmetric +/-1volt audio) As someone else said 8-bits resolution is 4 pixels on a modern screen, but this laptop so that?s how far the signal jumps. If you go for analog scopes then the screen size will be significantly smaller so you won't get anywhere near that resolution, and even on a very good scope I am pretty sure the spot size will be greater than 1 pixel. This laptop, which is typically what I use the USB scopes with is actually only 900 pixels vertically so about three pixels per step. Lastly I also own 2 analogue scopes, both old, a Tektronix 453 and a "no name" TV engineer scope that our local college sold when it stopped teaching TV repair. There are times when both of these are useful, but if I had to choose then I would take either of the USB scopes any day. In short I guess it is all down to what is called "opportunity cost". Spend $60 on a scope and the fastest CPU you can debug will be an 8Mhz z80 or 8086. For $200 you are in the higher speed 68030 arena... Dave G4UGM