Workout for scope and hifi.

[Murphyv310]

So does the cheap and cheerful Hitachi V-212.
I really must try and get a good working PSU for my Tek scope. That's the next job.

[Mark Hennessy]

It's pretty normal to have external X in some form - usually X-Y where one of the Y channels becomes X, so you have full control over amplitude, etc. In addition, some 'scope might have an external X mode, where the BNC normally used for external trigger becomes the X input. At least, that's what my Telequipment DM3 does. It's occasionally useful...

I suspect Ref was thinking about Z-mod.

Modern DSOs are a bit hit and miss when it comes to X-Y mode. It's usually present - often well-hidden in the menu structure - but the results can be a bit strange to look at.

These methods of measuring frequency by comparison to a separate oscillator are only really of use for low frequency stuff in my experience. At higher frequencies it's just too hard to get them to be close enough for comparison on a scope in either mode. However, the exception to that would be when comparing very stable oscillators like the 10MHz timebases in frequency counters. When it comes to setting one up against another, putting both traces on a dual-trace 'scope is actually the easiest way to do it IME

[ppppenguin]

Yes, you do need to be pretty close to get a meaningful display either with lissajous or dual trace display. The frequency knob on an average signal generator is rather coarse for this. I have a synthesised generator (part of my network analyser) that can be tuned in very fine steps indeed. When I'm working with TV related frequencies like PAL subcarrier my generator is actually not accurate enough to do an absolute measurement, where I need accuracy of the order of parts in 10^7. Perfectly OK for relative measurements. Most of us won't need that order of accuracy.

[Refugee]

I have just had a look at the manual for my scope.
The timebase plug in can get an X input from the front.
Z axis has to be done from the back as is buffered Y amp for the DFM.

[Mark Hennessy]

Yes, a Y-OUT is a useful facility, and not very commonplace - or at least, not as commonplace as I'd like. Often, if it exists, it has some peculiarity - such as being for channel 2 only in the case of the Tek 2465 (and no-doubt others in that range). In many cases, it's a factory option (so invariably not present!).

In the case of my Philips PM3295, the Y-OUT signal comes from selected trigger source for the delayed time base. That seems a bit peculiar at first - but then Philips aren't exactly known for following convention. Once you've got used to it, it's very handy indeed.

While most connect a frequency counter to the Y-OUT, I recommend trying a powered loudspeaker. For anything audio related - or power supply - it's amazing how much information you can pick out from the sound. And it saves having to have a working audio stage when working on a radio. On my Telequipment DM63, the only Y-OUT socket comes from one of the vertical plug-ins - the V3 differential plug-in, which is a low bandwidth (but high sensitivity) unit, so it acts like a signal tracer with an amazing dynamic range!

[ppppenguin]

I often connect the Y2 out of my 2465B to a small monochrome TV monitor. This monitor is sync'ed to my lab sync pulse generator so I can view all sorts of TV related signals simply by probing them. Very handy when I'm designing and debugging TV equipment.

[pwdrive]

My cheapo Tenma (GW Instek) has XY mode (CH1=X) Z in and Y out (CH1) Plus built in frequency counter linked to the Y amp.

Lawrence.

[Diabolical Artificer]

I have several scopes that have separate ext sync or horizontal IP. A HP 120B which is a single ch scope shows these visualizations/lissajous patterns well. My Tek 585 also has ext horizontal IP as well as several other ins and outs which I havn't figured out to use like + gate A and B, delayed trig, and ext rigs for both beams. It also works on my Tek SC502 which has timebase off on the hor timebase knob.

This facility is also very useful for curve tracers. I have built a simple component tester like a Octopus that you can use to test diodes, caps etc. Keep meaning to build a proper curve tracer but busy fettling the big amp.

Andy.

[ppppenguin]

One of these XY displays passed throuhg my hands some years ago: http://w140.com/tekwiki/wiki/602

I couldn't find a reason to keep it.

In the colour TV world, a vectorscope** is a specialised XY display, with B-Y on the X axis and R-Y on the Y axis. Even now when PAL and NTSC are obsolete, monitoring software still usually offers a vector display.

** Strictly speaking Vectorscope is a Tek trademark but harldy anyone uses the generic "vector monitor".