Most recent fixed-point filtering operation report
rlog = qreport(h)
rlog = qreport(h) returns
the logging report stored in the filter object
rlog. The ability to log features of
the filtering operation is integrated in the fixed-point filter object
Each time you filter a signal with
log data overwrites the results in the filter from the previous filtering
operation. To save the log from a filtering simulation, change the
name of the output argument for the operation before subsequent filtering
Also, you cannot use
Enable logging during filtering by setting
for your MATLAB session. Trigger logging by setting the
fixed-point filter and filtering an input signal.
Filter operation logging with
some preparation in MATLAB. Complete these steps before you use
Set the fixed-point object preference
on for your
MATLAB session. This setting enables data logging.
Create your fixed-point filter.
Filter a signal with the filter.
return the filtering information stored in the filter object.
qreport provides a way to instrument your
fixed-point filters and the resulting data log offers insight into
how the filter responds to a particular input data signal.
rlog contains a filter-structure-specific
list of internal signals for the filter. Each signal contains
Minimum and maximum values that were recorded during the last simulation. Minimum and maximum values correspond to values before quantization.
Representable numerical range of the word length and fraction length format
Number of overflows during filtering for that signal.
qreport depends on the
for fixed-point objects. This example demonstrates the process for
enabling and using
qreport to log the results
of filtering with a fixed-point filter.
hd is a
fixed-point direct-form FIR filter.
f = fipref('loggingmode','on'); hd = design(fdesign.lowpass,'equiripple'); hd.arithmetic = 'fixed'; fs = 1000; % Input sampling frequency. t = 0:1/fs:1.5; % Signal length = 1501 samples. x = sin(2*pi*10*t); % Amplitude = 1 sinusoid. y = filter(hd,x); rlog = qreport(hd)
View the logging report of a direct-form II, second-order sections
IIR filter the same way. While this example sets
you do that only once for a MATLAB session, unless you reset the mode
off during the session.
fipref('loggingmode','on'); hd = design(fdesign.lowpass,'ellip'); hd.arithmetic = 'fixed'; y = filter(hd,rand(100,1)); rlog = qreport(hd)