1/19/2008
Copyright
2005 – Tim Hoerning
26
Overflow & Headroom
•If a signal exceeds the maximum value represented by the
k-bit
system, then an overflow has
occurred.
–If this is detected, the signal can be clipped to the
maximum level. This will result is some distortion, but depending on the
level of the clip it may be
tolerable
–If unchecked, the signal will wrap around from the
positive side of the y-axis
to the negative because of the 2’s complement implementation. This
will cause a noticeable pop in the output waveform.
•The amount of signal level between the normal operating
point and the clipping point (or
the input overflow point) is the headroom.
Care should be taken in
selecting an input power level.
–Too low and the quantization noise will be apparent
–Too high and the headroom will be too low to handle the
dynamics of the signal