help to interpit specs of a function generator?

[lousyburger]

Hi im on the way of choosing a function generator.
I want one that is able to output a square and sine wave down to the hertz in accuracy...the accuracy is important.
I dont want the frequency to drift more than within one hertz during operation either.
I will output a frequency of for example 451 kHz (square and sin waves).

I want it to be able to produce totally positive offset square waves between for example 1 volt to 13 volt peak to peak.

i have thought about buying a "Victor VC2003"
it has specs as follows and I don't know how to interpit them:

Output scope of frequency 1Hz~3MHz
Frequency accuracy ±(5×10-5+10mHz +1)
Square wave distortion 20ns
Output amplitude 16Vp-p
DC deflexion ±6.4V


Output wave Sine wave , square wave distortion
Harmonic distortion -40dBс
Square wave distortion 20ns
Function output impedance 50Ω
Output amplitude 16Vp-p
DC deflexion ±6.4V
Inside amplitude modulating frequency 400Hz, 1kHz
Inside amplitude modulating depth 1%~100%
Outside amplitude signal frequency response 100Hz~100kHz
Outside amplitude modulating input impedance 600Ω
Frequency sweep time 0.02s~5s
Outside frequency measurement sensitivity 250mVrms
Dimension 270 ×215 ×100mm
Weight 1.9kg
Power AC 220V/110V 50Hz/60Hz


Thanks for all the help