Atec Agilent-8990B - Manual (Page 15)

15
Effect of video bandwidth setting
The noise per sample is reduced by applying the meter video bandwidth filter
setting (High, Medium or Low). If averaging is implemented, this will dominate
any effect of changing the video bandwidth.
Effect of time-gating on measurement noise
The measurement noise on a time-gated measurement will depend on the time
gate length. 100 averages are carried out every 1 µs of gate length. The Noise-
per-Sample contribution in this mode can approximately be reduced by
√(gate length/10 ns) to a limit of 50 nW.
1. Specified as 10 % to 90 % for rise time and 90 % to 10 % for fall time on a 0 dBm pulse.
2. Specified as the overshoot relative to the settled pulse top power.
3. In triggered mode with timebase setting at 4 msec/div
4. Within 1 hour after a zero, at a constant temperature, after 24 hours warm-up of the peak power analyzer. This component can be disregarded with
Auto-zero mode set to ON.
5. Measured over a one-minute interval, at a constant temperature, two standard deviations, with averaging set to 1.
Noise multiplier
Average setting 1 2 4 8 16 32 64 128 256 512 1024
< 500 MHz 1.00 0.75 0.55 0.40 0.35 0.30 0.25 0.22 0.21 0.20 0.19
> 500 MHz 1.00 0.73 0.52 0.37 0.28 0.21 0.17 0.15 0.14 0.14 0.14
Noise per sample multiplier
Video bandwidth setting
Low: 5 MHz Medium: 15 MHz High: 30 MHz Off
< 500 MHz 0.91 1
> 500 MHz 0.56 0.74 0.93 1
Dynamic response - rise time, fall time, and overshoot versus video bandwidth settings
Video bandwidth setting
Parameter Low: 5 MHz Medium: 15 MHz High: 30 MHz
Off
< 500 MHz > 500 MHz
Rise time/Fall time 1 < 60 ns < 25 ns < 13 ns < 50 ns ≤ 5.5 ns
Overshoot 2 < 5% < 5%
Noise and drift 3
Sensor model Zeroing
Zero set
Zero drift 4
Noise per
sample Measurement
noise
5 < 500 MHz > 500 MHz
N1923A/N1924A No RF on
input 200 nW
80 nW 3 µW 50 nW
RF present 550 nW 200 nW 80 nW 3 µW 50 nW
System Specifications and Characteristics
(continued)