On a DSO zoom mode is dual timebase model. You also have to realise that on an analog oscilloscope you will be looking at different sweeps (and thus different signals) where on a DSO you'll be looking at the same 'sweep'.
That is not correct as there are many DSOs which have both dual timebases *and* zoom mode; these are distinct features despite cheap manufacturers like Rigol presenting the later as the former. One way to identify true dual timebase DSOs is by the presence of separate trigger settings to support the second timebase; usually each timebase has an associated trigger.
A dual timebase DSO can use different sample rates for each acquisition record. Zoom displays an existing acquisition with a different time/div and therefor also works on stored waveforms. Zoom has largely replaced dual timebases because long record lengths allow for an extended operating range of zoom and it is less expensive to implement.
It is not universal that displaying dual timebases requires separate sweeps or acquisitions even on single beam instruments. Some analog oscilloscopes, like the 4 bay Tektronix 7000 series, support horizontal chop mode operation instead of only alternate mode operation between the timebases. There may be some DSOs which support the same thing although offhand I do not know of any; there is nothing which precludes it except for cost and complexity and it is a trivial change to support it.
Note that in the above, dual timebase really means dual delayed timebase. True dual independent timebase oscilloscopes whether analog or digital storage are very rare.
Hi there! Can somebody please explain the advantages of a Dual Timebase Oscilloscope?
I think you really mean dual delayed timebase oscilloscopes so I will only discuss them. Dual independent timebase oscilloscopes are very rare and essentially come down to having two independent oscilloscopes sharing the same display.
The obvious advantage of a dual delayed timebase is being able to magnify a feature for display however this is the least of it. For video work, it allows triggering on a video frame, and then displaying only a selected video line. For measurement work, the delayed timebase can be used to make precision slideback time measurements by aligning two different features on the CRT with the difference in the calibrated delay time control indicating the measured time. Since this uses the CRT as a null indicator, CRT accuracy is not a factor in the measurement. An extension of this is the dual delta delayed timebase oscilloscope which can display the delayed timebase with two different delay settings.
DSOs can make measurements directly without slideback measurements. Zoom supported by large record lengths allows for good magnification capability. On the other hand, selecting a waveform feature to display still requires a dual delayed timebase for the triggering capability, but this is not a common requirement anymore although I like to use it with switching power supplies.
I know that 2 Channel Digital scopes have an advantage over Analog, as the trace on a Analog on Alternate isn't "Real-Time", because the two sweeps are done one after the other.
Some analog oscilloscopes can capture more than one sweep at a time. This can be done with dual independent beam instruments, which are effectively two oscilloscopes sharing the same display, or by chopping the horizontal signals between two timebases like with the Tektronix 4 bay 7000 series.
But on a Digital - from what I've been told, doesn't have a slow chop mode (1 Khz or so) , but alternates between the pixels of the dual channels, basically in my view, would be beter for comparing 'High Speed Signals' between channels than an Analog.Am I right?
Some early DSOs also supported user selectable alternate and chop mode but now this is done automatically. DSOs which interleave their ADCs between channels effectively chop between active channels or groups of channels between samples but as a practical matter, acquisitions can be considered simultaneous. "Real time" as applied to DSOs used to mean simultaneous acquisitions on multiple channels with independent digitizers.