Tone generator voltage divider.

I was trying to calibrate colin's Ez760, but it got a little tedious measuring the output from my tone generator in order to set it every time it changes in the guide.  (last 3 pages, but not essential for my question - https://pcbgrinder.com/download/EZ760_colourbook.pdf)

I need the following 1Khz outputs, and I figured it might be possible to set the output of my tone generator to 0,2dBU and put the rest on a switch.

0,2dBu (0,79V)
0dBu (0,775V)
-30dBu (0,025V)
-34dBu (0,015V)

Would it make sense to set up a voltage divider and put R2 on the switch with a fixed R1 value? (Editr alternatively, use a 2x6 switch to put both values on the switch). Would it compromise my measurements? And is there a any set way to think about the ratio of R1 and R2 (one should be bigger, ratio should stay close to x or similar)




Gustav

Seems to be working, so no bother.

Gustav

Isn't a bad Idea to have an output buffer to have constant output impedance.

JS

joaquins said:

Isn't a bad Idea to have an output buffer to have constant output impedance.

JS

Click to expand...

You're right, of course -  I had to add a buffer after trying it "in circuit".  :-[ Always learning! 

Gustav

Depending on your circuit loads you would came out with diferents levels, as long as if you take that in consideration it's ok.

JS

Sorry I am too late.

If the signal generator will drive a true 600 Ohms, then this will give your levels. 1P4T switch. No buffer should be needed; worst-case output impedance is under 19 Ohms (after you calibrate for 0.79V on the top tap with the EZ760 connected).

Nearest 5% values are probably OK. 2% parts are sure to be "perfect" enough.