Hooking unbalanced test equipment to balanced circuit
Posted: Mon Nov 22, 2010 8:57 am
I've got a question about unbalanced test equipment being hooked to balanced gear.
For example:
If I send a balanced 0dBu 1kHz sine wave to my gear on an XLR connector, that'll be 2.19V p-p. This means it would be 1.095V on each leg of the balanced connector, right? (pin 1-pin2, and pin1-pin3 on XLR).
That way, when an unbalancing circuit sums them (and inverts the pin1-pin3 signal), they'll sum to 2.19V p-p, or .775V rms.
Right?
So, if I have an unbalanced signal generator, and I hook it up at 2.19V p-p between pins 1 and 2, that will give essentially the same result, because there will be no input on pin 1-pin3, so there will be no addition to the signal; we just won't get the benefit of CMRR.
Does that sound right? Anybody know?
Thanks!
Mike
For example:
If I send a balanced 0dBu 1kHz sine wave to my gear on an XLR connector, that'll be 2.19V p-p. This means it would be 1.095V on each leg of the balanced connector, right? (pin 1-pin2, and pin1-pin3 on XLR).
That way, when an unbalancing circuit sums them (and inverts the pin1-pin3 signal), they'll sum to 2.19V p-p, or .775V rms.
Right?
So, if I have an unbalanced signal generator, and I hook it up at 2.19V p-p between pins 1 and 2, that will give essentially the same result, because there will be no input on pin 1-pin3, so there will be no addition to the signal; we just won't get the benefit of CMRR.
Does that sound right? Anybody know?
Thanks!
Mike