Jan,
A couple of thoughts about testing your super duper stuff.
Test the noise performance without the test signal, with the input shorted. Send the output through a 100 times gain known quality instrument amplifier. (OPA1612?) That output goes into your System 2 analyzer. Is the super duper stuff worthy? If yes then next.
If you are looking for better than -134dB 2nd harmonic take the SDS down the road to you neighbors APx555 that is good for -150ish dB 2nd harmonic. If yes then stop, else.
Or split the generator output send half to your DUT the other half to the inverting input of an OPA1612. Sum the outputs of your DUT and the inverted instrument OPA1612, the test input signal fundamental and harmonics will null. What remains is only the DUT error output. Send the amplified error output to your System 2 analyzer. See Figure 34 in the OPA1612 data sheet. This is the stuff of error correction.
http://www.ti.com/lit/ds/symlink/opa1612.pdf
Or I could be full of it.
Thanks DT
New out of the box unbalanced APx555.
A couple of thoughts about testing your super duper stuff.
Test the noise performance without the test signal, with the input shorted. Send the output through a 100 times gain known quality instrument amplifier. (OPA1612?) That output goes into your System 2 analyzer. Is the super duper stuff worthy? If yes then next.
If you are looking for better than -134dB 2nd harmonic take the SDS down the road to you neighbors APx555 that is good for -150ish dB 2nd harmonic. If yes then stop, else.
Or split the generator output send half to your DUT the other half to the inverting input of an OPA1612. Sum the outputs of your DUT and the inverted instrument OPA1612, the test input signal fundamental and harmonics will null. What remains is only the DUT error output. Send the amplified error output to your System 2 analyzer. See Figure 34 in the OPA1612 data sheet. This is the stuff of error correction.
http://www.ti.com/lit/ds/symlink/opa1612.pdf
Or I could be full of it.
Thanks DT
New out of the box unbalanced APx555.
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