Which is more accurate: digital or vinyl?

Nil, yes the number of samples (for each cycle of each frequency component of the analog signal that is being digitized) increases as you described, as the analog signal frequency decreases. Hi rez also increases the number of samples per cycle. For instance, a 192 kHz sample rate provides 192/44.1 = 4.35 times as many samples as redbook cd's 44.1 kHz sample rate.

However, what is often not recognized is that the problem with having a finite sample rate and a relatively limited number of samples of high frequency components in the signal is not "gaps," per se. In theory, if an infinitely long analog waveform is digitized using a sample rate that is at least twice the frequency of the highest frequency component of the analog signal, and if the number of bits per sample are high enough to reduce what is called "quantization noise" to insignificant levels, the digital data can be converted back to analog perfectly, with no loss of information in the "gaps."

Arguably the most significant theoretical issue, however, is that frequency components in the original analog signal that equal or exceed half the sample rate MUST be kept out of the a/d converter, or they will be reconstructed following d/a conversion as spurious lower frequencies (referred to as "alias frequencies"). Keeping those frequencies out of the a/d converter, while at the same time avoiding side-effects on audible frequencies, has historically been one of the most major technical challenges in digital. Hi rez formats certainly have a big advantage with that issue, all else being equal, as 96 and 192 kHz exceed twice the highest audible frequency (nominally 20 kHz x 2 = 40 kHz) by a far larger factor than redbook's 44.1 kHz.

Best regards,
-- Al

Al,
I used to argue that digital is a sampling of analogue but there are more fundamental issues. It is relatively easy to fill in the gaps using mathematical modelling.
The real issue with digital is the Red Book Standard and the use of sine x/x.
I'm sure you are aware the use of sine x/x means that all the calculations are truncated.
If they had used tan x for example the calculations would have yielded whole numbers and there would be no truncation errors.
My view is that digital is fundamentally flawed, not because of the concept, but due to the maths being incorrect and the way it has been implemented..
One of the biggest issues in developing digital product is that most audio engineers are engineers not mathematicians.

I am very used to hearing things that are hard to see on the oscilloscope. Interestingly, instrument manufacturers use a different rule for scanning a signal. The rule of thumb is 10x the highest frequency to be displayed.

This is quite different from what we see in audio, where Redbook only asks for 2x the highest frequency to be reproduced.

The instrument manufacturers use higher scan frequencies in order to maintain waveform fidelity. This is not the case in audio, seems to me that audio reproduction has been treated as the poorer cousin.

Atmasphere, I have to agree that audio does seem to get the short end of the stick, and has for a very long time. After all, it would seem to me that the original cylinders would be a better performing platform than the flatform record platters that replaced them.

The tapes were baked because they used a synthetic tape lubrication not whale oil based lubricant. Overtime they became unplayable. Record companies were in a frantic panic to find a solution. The solution? Bake the tape. It can be played back within I think 48 hrs. You can bake it again, but don't know how many times! Steely Dan goucho had to be re-baked to do the sacd version.