Just to confirm that my upgraded DS1054Z has a measured bandwidth of ~130 MHz, confirmed both by using a leveled signal generator (looking for the -3 dB point), and a pulse generator with a 70 ps risetime. On the system info screen the system software is 00.04.01.SP2, the board version is 0.1.1, and the model is shown as a DS1104Z.
What did it have before?
What does if have with different numbers of channels enabled?
Before the "upgrade" I measured the bandwidth as almost exactly 50 MHz with a sharp rolloff above 50 MHz, consistent with bandwidth limiting in software.
There is no
real difference in the bandwidth with multiple channels enabled (see the next paragraph), however, the sample rate drops to 500 MSa/s with two channels enabled, and to 250 MSa/s with three or four channels enabled. The memory depth drops from 24 MSa with one channel to 12 MSa/channel with two channels, and down to 6 MSa/channel with three or four channels enabled.
Because of the slower maximum sample rate with multiple channels enabled, there will be some waveform distortion due to undersampling at the highest sweep speeds. For example, at 5 ns/div a 250 MSa/s sample rate gives only slightly more than one sample per division, so fast waveforms can become very distorted. Changing the acquisition mode to Hi Res or Peak has no particular effect, nor would I expect any, since the samplers are already at their maximum speed. Averaging definitely smooths the waveform, but then there's no way to tell just by looking at it that there's an undersampling problem.
BTW, the risetime of a 70 ps risetime pulse generator as measured by the DS1054Z actually appeared to
improve by going from one channel to two channels enabled. That was just an artifact, because the slower sample rate missed some roundoff in the leading edge so the reconstruction by the sin(x)/x interpolator made the edge look faster. Enabling three or four channels slowed the risetime measurement due distortion of the leading edge caused by undersampling.