Time varying gain control
TimeVaryingGain object applies a time varying
gain to input signals. Time varying gain (TVG) is sometimes called
automatic gain control (AGC).
To apply the time varying gain to the signal:
Starting in R2016b, instead of using the
to perform the operation defined by the System
object™, you can
call the object with arguments, as if it were a function. For example,
= step(obj,x) and
y = obj(x) perform
H = phased.TimeVaryingGain creates a time
varying gain control System
object applies a time varying gain to the input signal to compensate
for the signal power loss due to the range.
H = phased.TimeVaryingGain( creates
H, with each specified property Name
set to the specified Value. You can specify additional name-value
pair arguments in any order as (
Source of range losses
Specify the source of range losses as either
Loss at each input sample range
Specify the loss due to range as a vector — elements correspond to the samples in the input signal. Units are in dB.
Loss at reference range
Specify the loss at a given reference range as a scalar. Units are in dB.
|step||Apply time varying gains to input signal|
Apply time varying gain to a signal to compensate for signal power loss due to range.
First, create a signal with range loss. Set the reference loss to 16 dB.
rngloss = 10:22; refloss = 16; t = (1:length(rngloss))'; x = 1./db2mag(rngloss(:));
Then add gain to compensate for range loss.
gain = phased.TimeVaryingGain('RangeLoss',rngloss,'ReferenceLoss',refloss); y = gain(x);
Plot the signal with loss and the compensated signal.
tref = find(rngloss==refloss); stem([t t],[abs(x) abs(y)]) hold on stem(tref,x(tref),'filled','r') xlabel('Time (s)'); ylabel('Magnitude (V)') grid on legend('Before time varying gain','After time varying gain',... 'Reference range')
 Edde, B. Radar: Principles, Technology, Applications. Englewood Cliffs, NJ: Prentice Hall, 1993.
 Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGraw-Hill, 2001.
Usage notes and limitations:
See System Objects in MATLAB Code Generation (MATLAB Coder).