@Ralph define "low" here

also, what degree of agility are you after?

@rdtsc thanks. Looks like the AD9850 has ~84 dBc @ ~5Mhz (narrowband). This would be even better/higher (e.g. 90 dBc) for a 1 khz sinewave? But I guess I didn't mention it should be as low noise as possible; I'm worried 10-bit DAC quantizaton noise is too high (snr = 6.02 * enob + 2.76 =~ 63 dB). Would prefer snr/sndr > 100 dB.

@Shalvenay By "low" I mean something similar to the DS360, which has -100 dBc distortion and 0.001% THD (below 20 khz). Forgive me, I'm not super familiar with the term 'agile'. This means latency between switching between frequencies / amplitudes? (in that case, no agility needed). Just trying to characterize an AFE (LNA, PGA, ADC) with small input range (5 mvpp)

@Ralph hm, is there a reason you're only characterizing it for sines? I'd almost think it'd be easier to generate a clean square wave....

(i.e. a 0-5mVpp square wave at some low frequency, and use it to characterize the system via its step response)