8060A
Instruction Manual
3-4
Signal
Generator
Amplifier Load
Bandwidth (BW)
f
1
f
2
Ff
C
0 dBdB Rel. Ref. Level
-3 dB
8060A
dx22f.eps
Figure 3-1. Measuring Amplifier Bandwidth
5. Increase the frequency input until the dB readings drop to -3.00 dB.
Press the Hz button on the 8060A to read the upper frequency limit of
the bandwidth. Press the dB button to restore the dB reading.
6. Decrease the frequency input so the dB readings rise to 0 dB and then
drop again to -3.00 dB. Press the Hz button to read the lower frequency
limit of the bandwidth.
You can use a similar technique to examine the performance characteristics
of frequency-sensitive filters, such as high or low-pass filters, notch filters,
etc. With the 4½ digit frequency resolution and the 0.01 dB resolution, you
can very accurately determine the rolloff, slope, and bandpass.
3-3. Using the 8060A as a Q-Meter
You can use the 8060A to determine the Q factor of a tuned circuit (refer to
Figure 3-2). First use the technique presented in section 3-2 to determine the
center frequency (fc) and bandwidth of the circuit (for tuned circuits, the
center frequency of the bandwidth is found at the peak or midway within the
high plateau of the dB readings). Then calculate the Q of the circuit by using
the following formula:
Q =fc/Bandwidth
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