14-07-2020, 12:05 PM
(14-07-2020, 06:48 AM)radioman Wrote: Thanks Mark for your observations : TBH I don't really have a specific application right at the moment.
There are a few projects I'm considering building that are microcontroller based and I thought that the serial decoding function could be useful.
I also think that the FFT would be nice to have as well for general use.
A radio amateur friend asked me about this particular model but I am well out of my depth with modern test equipment.
My current 'scope is a Tektronix 2445A which has four channels and in all the time I've had it I've never needed to use more than two channels so bandwidth is more important to me.
Sorry to Bushbaby for hijacking this thread.
Andy
It's worth mentioning that some serial protocols (like SPI) are 3-wire, so that's where the extra channels might come in handy. But check the user guides, because they might be able to use the external trigger input as that 3rd input.
My favourite 'scope - the Telequipment DM63 - can be 4 channel, depending on what plug-ins you have, but I will admit that it's not often I've needed more than 2. But on the occasions you do, it's essential!
I've never needed 3 or 4 channels at the same time as I've needed high bandwidth, so a 20MHz 4 channel 'scope in conjunction with a 350MHz dual channel 'scope covers all my analogue bases. Actually, for some years now, I've had a differential plugin in the DM63, so along with the dual V4 plugin on the other side, it's a 3 channel 'scope. The V3 differential plugin is really useful - it goes down to 50uV/division, and although the BW is lousy, it's one of my most-used channels. That's because I do a lot of audio, where low levels and the need for differential probing because of earth loops are commonplace. And that's why it's so hard to give advice about 'scopes - we all have our specific needs.
A lot of scopes now have an MSO (mixed signal) option, so are becoming a hybrid of a scope and a logic analyser. Makes sense - why have 4 or more expensive high quality analogue input stages when most people will be using the extra channels for logic signals? That's the thinking behind the "crippled" 3rd and 4th channels on the Tek 2400-series 'scopes - quotes because it's not meant as criticism, rather it's a pragmatic decision to not make them fully-featured given their likely use. After all, a lot of the time they're just used as an external trigger input.
