MOTM

On 24 Mar 2007, at 01:43, jneilyahoo@... wrote:

> For example, is there a reference standard for calibrating these  
> things?
> Or should I just send a full-strength signal out of the modular and  
> tweak
> things until the waveform fills the screen?  Right now I'm not seeing
> enough amplitude, and I'd rather keep an amplifier out of the input  
> path
> if I can.

I'll give this a try...

I usually keep the vertical scale at some calibrated value. A lot of  
scopes have a separate gain setting for each channel, separate from  
the V/div setting. I keep it at the default ('calibrated') setting,  
so that I can read off the waveform's amplitude from the screen.

Keep in mind that some probes have a 10:1 attenuation built in. If  
your scope has a 5 mV/div max sensitivity, this will become 50 mV/ 
div. Some scopes might show some noise (up to 0.2 or 0.4 div on your  
screen) on their most sensitive setting, so it is best to avoid this.

This makes it difficult to focus on low-level signals. Use a 1:1  
probe, or a switchable 10:1 / 1:1. However, you will need the 10:1  
probe if you need to measure on a high-impedance circuit. For the  
analog inputs and outputs a 1:1 probe will do just fine, and you can  
set your scope to something like 1 V/Div to start with.

It is kind of odd that you have trouble filling the scope's screen  
(if I understand you correctly) with the output of an MOTM module. It  
really shouldn't be a problem. Have you checked your probes?

With kind regards,
Ben