I could not find any information regarding the increase in bits in resolution for HiRes mode. Is there any information available?

The increase in bits in resolution depends on the decimation ratio.  The decimation ratio can be determined as follows:

D = MFs / Fs

MFs is the maximum non-interleaved sampling frequency of the scope.  For example: 5 GS/s for the DPO4104B or 2.5 GS/s for the DPO4014B models.  (Refer to the individual instrument's listed single channel sample rate.)

Fs is the sampling frequency that is displayed next to the time/div readout below the graticule.

The increase in bits over the original 8-bits of resolution is given by:
Enhanced Resolution Bits =  0.5 Log 2 ( D )

The table below therfore uses:
Bits of Resolution =  0.5 Log 2 ( D ) + 8

The HiRes smoothing algorithm performs a digital boxcar filter on the decimated acquisition, reducing its bandwidth.  The 3 dB bandwidth for HiRes mode is approximately 0.44 of the sample rate.

The following tables indicate the Bits of Resolution obtained for selected sample rates.  Note that the only reliable way for a customer to know what the bits of resolution and bandwidth are is by looking at the sample rate readout.  You cannot use time/div, since that varies the sample rate depending on the record length.

In order to make the table more usable by customers, we have used product sample rates, rather than using power-of-two decimation factors, which would be more precise.  For that reason, the table doesn’t follow a nice 1, 2.5, 5 sample rate ratio, because our goal was to find the closest power-of-two, in order to have it progress by bits of resolution.

HiRes example results at 5 GS/s base sample rate (e.g. DPO4104B)

HiRes example results at 2.5 GS/s base sample rate (e.g. DPO4014)

* The maximum HiRes bandwidth is further limited by the analog bandwidth.