Increasing voltage source frequency
First of all, frequency is not voltage dependent. Secondly, I'm not really sure what you want to achieve. What kind of waveform do you want to have (Pulse, Sinus...)?

If you want to have a pulse voltage output you can use 


  PULSE(0 5 0 0 0 0.5m 1m 100)


which will generate a 5V pulse voltage with a frequency of 1kHz and 50% Duty Cycle. The pulse will be repeated 100 cycles.