Understanding Unitrunker tuner log

I am curious what data in my tuner log means. I have been looking at a tuner log and see many things there. I don't know if I'm to interpret it as being a problem or whether to know everything is working the way it is supposed to. Here is a sample of a tuner log:


I am curious what the different numbers represent. I see the word "error" quite frequently but don't know what kind of an error is occurring so I have no idea how to correct it. The "prescale" is always "1" and "Quotient" is always "59" but I have no idea what that means. Also, I see every few lines, a line about gain and four sets of hexadecimals... what do they indicate? Inquiring minds want to know.

When someone has problems with their radio - it is often easier to ask for a log file than ask twenty questions to understand what exactly they were doing when a problem occurs.

This log entry describes the registers used to program the R820T(2).

PLL LO 856907000 prescale 1 Quotient 59 SDM 33254 error 213.

This tells me the local oscillator was tuned to 856907000 (which is 3.58 Mhz above or below the true center frequency). The PLL - like most PLLs - uses a digital divider to divide the oscillator down to something that can be compared to a reference clock (in this case - the 28.8 Mhz crystal that also runs the Realtek chip). The pre-scaler is a power of two so the oscillator is divided by 2. The quotient is used to divide the oscillator down further. The SDM value is the remainder.

You can google "Fractional N PLL" and "Sigma Delta Modulator" to learn more than you ever wanted to know about the subject.

The error value is the estimated error due to integer truncation in the PLL. In this case, the actual frequency was 213 hertz (that's HERTZ) off of the desired frequency.

In this next example, estimated error was only 67 hertz.

PLL LO 856907000 prescale 1 Quotient 59 SDM 33259 error 67.

The gain values are actually four status registers in the R820T sampled at the time the gain registers were set.