"Trevor Wilson" wrote in message

David Looser wrote:
"Trevor Wilson" wrote in
message ...

"Brian Gaff" wrote in message
om...
We used to use squarewaves for the following.
To show how bad tape machines were...
To show the tone control effects

However, you need to look at the harmonics on a true
square wave, which of course cannot actually exist.

**If you REALLY want to laugh, look at a 7kHz square
wave from a CD player (even 5kHz is barely passable
from most CD players). A good R-R or high end vinyl
playback can do a MUCH better job.

Bull****

Agreed.

**Red Book CD tops out at 22.05kHz. A decent RR can
easily top 30kHz. A top of the line vinyl rig can easily
manage 60kHz. Do the math.

The math includes the phase response. If a system is linear phase or minumum
phase then there is a mathematical relationship between amplitude and phase.
In the general case, there is no such necessary relationship.

Modern D/A and A/D converters are generally generally based on phase linear
filters.

Both LP and analog tape playback is far from being either minimum phase or
linear phase because of their transfer function is based on both minimum
phase and non-minimum phase filtering. The minimum phase elements are
electronic, and the non-minimum phase elements are based on the fact that
they both involve moving media with mechanical and/or magnetic wavelength
effects.

Bottom line, it is not uncommon to have wide bandwidth, but with many
unpredictable phase changes. Well the phase changes are unpredictable until
you understand more details about how they work.

In general analog tape machines have far poorer square wave response than
their actual frequency response predicts because of wavelength effects
related to the head gaps.