Specifications

7
Measurements in the linear operating region of the
amplifier can be made with the 8510C by using the
basic setup shown in Figure 2. Care must be taken
when setting the input power to the AUT so that it
is operating within its linear region.
1. Configure the system as shown in Figure 2.
Return the 8510C to a known state of operation.
[RECALL]
[MORE]
[FACTORY PRESET]
2. Choose the appropriate measurement parame-
ters (start/stop frequency, number of points,
power, etc). The power level should be set such
that the AUT is operating in its linear region. In
this measurement example, an estimated input
power level of –15 dBm is derived from:
P
in
= P
1dB
– Gain – 10 dB
= +25 dBm – 30 dB – 10 dB
= –15 dBm
[START] [2] [G/n]
[STOP] [26.5] [G/n]
STIMULUS [MENU]
{POWER SOURCE 1} [–15] [x1]
3. Perform a full two-port calibration. If attenua-
tors are used on the output of the amplifier they
should be included in the calibration. In this exam-
ple, a 20 dB fixed attenuator on port 2 prevents
the +25 dBm of output power from overdriving the
port 2 input of the 8517B. Save the instrument
state to one of the internal registers.
[SAVE]
{INST STATE 1}
4. Connect the AUT and apply bias, if necessary.
Small signal gain/gain flatness
Small signal gain is typically measured at a con-
stant input power over a swept frequency range.
1. Set up the 8510C for an S
21
log magnitude meas-
urement.
[S21] [LOG MAG]
2. Scale the display for optimum viewing and use a
marker to measure the small signal gain at a
desired frequency.
Linear measurements
Figure 2. Basic setup for amplifier measurement using the
8510C network analyzer
Figure 3. Small signal gain measurement
AUT
Thru
Open
Short
Load
Attenuator
(if needed)