Dear DC1MC,
It seems thar it is again a basic GPSDO with the traditional 1pps comparison.
Have a look at the description of the Fluke 910 and 910R. The limitation of the DSO are clearly explained :
"Two high-stability operating modes to suit your application
Most users prefer automatic adjustment (known as disciplining) of their frequency standard, to fully eliminate long-term frequency changes (aging). This disciplined mode is also the default mode in the 910 and 910R. As long as there is a valid satellite signal, the internal local oscillator is monitored and adjusted and the mean 24-hour frequency offset is always virtually zero. However, in this mode, the inherent short-to-medium term stability of all local oscillators, except rubidium, is compromised. This is true for all GPS frequency references. The received GPS signal has relatively large short-term frequency variations, due to variations in atmospheric conditions. This means that when using the received GPS signal for disciplining the 910 (OXCO), the stability is reduced a little for averaging times of 100 s to 1000 s.
In this mode, the frequency deviation between the internal timebase oscillator and the received GPS-signal is used to continuously adjust the oscillator (disciplining). The resulting frequency offset and adjustment data is stored in non-volatile memory every 24 hours, to enable printout of the traceability record. The actual frequency offset (24-hour mean value) is calculated and displayed on the front panel.
Some applications demand superior short-medium term stability, especially for jitter and wander measurements in digital telecommunication networks.
The unique Manual Hold-Over Mode makes it possible to switch over temporarily from Disciplined to Hold-Over Mode during the actual measurement, thereby achieving a superior frequency accuracy at the start of the measurement and a superior stability through the measurement. Here, the internal oscillator is not adjusted. This mode is normally automatically entered when there is no usable received GPS-signal. This mode can also be selected manually by activating the Manual Hold-Over Key. If Manual Hold-Over is set together with a valid received GPS signal, the actual frequency offset is calculated, displayed and stored in non-volatile memory every 24 hours.
For the ultra-stable rubidium oscillator in the 910R, there is no measurable difference between the stability in Disciplined and Hold-Over mode, for averaging times up to 1000 s."