voltage domain to time domain conversion

In conventional ADC we quantize in voltage domain... but as technology scales it is difficult to quatize in voltage domain..In VCO based ADC the voltage domain is converted to time domain... I want to know what is voltage domain exactly... I know signal represented in time and frequency domain... but what is voltage domain??? does voltage domain represent the signal amplitude??? I saw a signal in time and freq domain... the time domain (that had sum of many signals) was as a continuous waveform as it was plotted amplitude in x axis and time in y.... but that in freq domain just represented the max amplitude of each signal as a single line with amplitude in x axis and freq in y... so time domain and freq domain both contain voltage amplitude information... atleast freq domain represents the max amplitude of the signal but the time domain contains the voltage amplitude from max to min so how is it different from voltage domain??? am I confused... if yes then can someone please help me out...

Ouch !!

I think you need to go step by step and get your concepts clear one by one.

Fundamentaly I think your confusion is in understanding time domainsignal representation, Vs frequency domain signal representation.

Never mind what an ADC or a VCO does or does not do. Instead get hold of a basic book/ writeup on the Fourier transform. Study the initial few chapters - that should help clear up some of your confusion.