modulation bandwidth of VCO [hlp]

Hello Everyone;
What's the meaning of modulation bandwidth of VCO? Please explain. Also which modulation bandwidth is better: 1MHz or 12MHz? Why?

I think you may relate to Kvco. The bigger the kvco the more sensitive to modulation signal. However, the phase noise performance gets worse as kvco goes up. Therefore, it is hard to say which is better ( 1Mhz or 12MHz ), it is dependent on your system requirement.

For Example see this table:

I think it is the highest frequency of the modulation signal, at wich the frequency deviation can be estimated using Kvco, and the modulating voltage.
The VCO cant change its frequency in an instant, it acts as if the control voltage was aplied through an low pass filter. The output frequency evoluates to the value specified by the control voltage and Kvco in a finite amount of time.

Thus, if you aply a modulation signal with frequency higher than 11MHz, you would get a smaller frequency deviation than for lower frequency modulation signals. (considering the same modulation voltage)