Digital Signal Processing Reference
In-Depth Information
C
= 3.4 nF
+
+
Port 1:
Input
Port 2:
Output
R
=4.7 k
Ω
-
-
FIGURE 1.9
Low-pass filter circuit with 10 kHz cutoff frequency.
•
In this experiment, frequency response measurements will be per-
formed using the HP 35665 Dynamic Signal Analyzer.
a.
The Dynamic Signal Analyzer can measure the frequency re-
sponse of a passive device, such as an electrical filter, for example,
in the frequency range of 0 to 50 kHz, In this experiment, we will
determine the frequency response of a low-pass filter, having a
cutoff frequency of 10 kHz.
b.
Build the filter circuit shown in Figure 1.9, with port 1 as the
input
port
and port 2 as the
output port
. Since the circuit is quite simple,
it can be put together even on a breadboard for testing. However,
a permanent circuit soldered together would be more ideal.
c.
Connect the filter circuit to the HP 35665 Signal Analyzer as
shown in
Figure 1.10
.
The source output of the Signal Analyzer
is simultaneously connected to the input port of the filter circuit
and also to
channel 1
(Ch1) of the Signal Analyzer, while the
output port of the filter circuit is connected to
channel 2
(Ch2)
of the Signal Analyzer.
d.
It is important to set the Signal Analyzer settings appropriately
to obtain the frequency response of the filter circuit. Select the
frequency
key on the Signal Analyzer, and set the
start
and
stop
frequencies to 0 Hz and 20 KHz, respectively. Select the
measure
key, and set the measurement to
2 channel
measurements, and
then select
frequency response
setting. Select the
source
key,
and set the source to
chirp
signal, which will generate a swept
