10-08-2015, 03:39 PM
Ah, but not everyone has our wisdom. That's a diplomatic way to say that we've been doing this a long time 
Some of our trainees are quite upset when they see a high BW 'scope because they've come through university using basic 20MHz models for everyday experiments and wouldn't necessarily consider the noise question. To be honest, whatever 'scope manufacturers might say, I bet that is one motivation for including the 20MHz mode. Personally, I'd label it "SET FOCUS"
Our 2400-series 'scopes have had relatively little use, and they are still pretty sharp. Just a couple of weeks back, I was comparing them to a well-worn example that we rescued from TVC, and that has been really hammered over the years. Still usable, but definitely a bit soft. Probably the sharpest 'scopes I've seen are the various Philips models - PM3055 and onwards, with high PDA and sorted electronics (all-electronic with just a few reed relays here and there). My later Combiscope also fits that category - very nice indeed. Our 7000-series model is as soft as anything, but that is a storage model if that makes any difference? My DM63 is also a storage 'scope, but is also sharp - but doesn't go as bright as the Philips. Clearly, there's a lot of art that goes into the design of the CRTs - quite how they work at the write speeds they do is beyond me.
I finally took the plunge and brought a Rigol DS1054Z. Annoyingly, the price has fallen by 20 quid since I bought it. I plan to start a thread in a couple of weeks time, but first impressions are very good indeed. Analogue video looks especially good - although I'm no expert on video. For single-shot stuff, it's amazing - the extent to which you can pan and zoom the acquired trace really impressed me - it'll be excellent for doing digital stuff. More later...
Some of our trainees are quite upset when they see a high BW 'scope because they've come through university using basic 20MHz models for everyday experiments and wouldn't necessarily consider the noise question. To be honest, whatever 'scope manufacturers might say, I bet that is one motivation for including the 20MHz mode. Personally, I'd label it "SET FOCUS"
Our 2400-series 'scopes have had relatively little use, and they are still pretty sharp. Just a couple of weeks back, I was comparing them to a well-worn example that we rescued from TVC, and that has been really hammered over the years. Still usable, but definitely a bit soft. Probably the sharpest 'scopes I've seen are the various Philips models - PM3055 and onwards, with high PDA and sorted electronics (all-electronic with just a few reed relays here and there). My later Combiscope also fits that category - very nice indeed. Our 7000-series model is as soft as anything, but that is a storage model if that makes any difference? My DM63 is also a storage 'scope, but is also sharp - but doesn't go as bright as the Philips. Clearly, there's a lot of art that goes into the design of the CRTs - quite how they work at the write speeds they do is beyond me.
I finally took the plunge and brought a Rigol DS1054Z. Annoyingly, the price has fallen by 20 quid since I bought it. I plan to start a thread in a couple of weeks time, but first impressions are very good indeed. Analogue video looks especially good - although I'm no expert on video. For single-shot stuff, it's amazing - the extent to which you can pan and zoom the acquired trace really impressed me - it'll be excellent for doing digital stuff. More later...
