Digital Filters deal only with samples, right?

I'm new to digital filters. So I'm trying to get things right and I can't find an explicit answer to my question on the internet.

Question: Digital filters only accept samples as input? I mean the input can not be zeros nor ones. It can only be samples. If that's the case, then the typical position for a digital filter would be after the receiver (I mean before converting to bits).

So receiver would be like:

$$\mbox{antenna} \rightarrow \mbox{amplifier} \rightarrow \mbox{Sampler} \rightarrow \mbox{Digital Filter} \rightarrow \underbrace{\mbox{DAC}}_{\tiny \mbox{here I should have filtered samples}}$$

Please correct me and kindly ignore any coding or LNAs and stuff like that.

• Welcome to DSP.SE! Why do you have a DAC after the digital filter in your flow? There is nothing stopping you applying a digital filter to zeros and ones, but that would not be the normal use. Usually one or more filters is/are applied to the received (probably downconverted) signal. – Peter K. May 17 '16 at 11:37