Does a DVD recorder with a digital tuner allow you to record one channel while watching another channel?

It depends on the set you are watching on and your cable service.

If you have a cable service that sends in all channels, digital and analog, without the need for a set top box, then you can get all the channels available if your DVR and television both have digital tuners built into them.

If your DVR does not have a digital tuner, it will only be able to pick up the standard channels and not the "virtual" channels available through digital service (i.e. 8.1 or 17.4, etc.). If the DVR does have a digital tuner, but you are still watching on an old analog CRT television set, then you won't be able to watch the virtual channels while the DVR is recording, since the old TV won't pick up those in between channels.

So, the answer is, if you have a set with a digital tuner, and a DVR with a digital tuner, you will be able to watch any channel while recording any other channel, as long as they are not encoded. If one of the two does not have a digital tuner, then your watching selection will be limited to what it can pick up.