HP 70427A User Manual page 469

Block Diagram
HP 70428A Microwave Deck Assembly
Currently, the SRD/edge-sharpener combination has a rise time of about 13
ps, measured between 10% and 90% of the pulse amplitude. The result is a
usable frequency range of 600 MHz to 25.8 GHz.
A 26.5 GHz, 3 dB attenuator has been integrated into the edge-sharpener's
package to insure the SRD/edge-sharpener combination is terminated in a
minimum of 6 dB return-loss for all usable output frequencies when
connected to the YTF. This is necessary to prevent spurious oscillations in
the SRD.
YIG-Tuned-Filter (YTF)
The YTF is a three resonator filter tunable from 2.4 to 26.5 GHz. The filter is
used to select the desired comb frequency, and reject the undesired signals.
It is necessary to remove unwanted comb frequency before the desired signal
is amplified to prevent amplifier output saturation. The power in all the comb
line frequencies together is about +23 dBm to +27 dBm although any
individual comb frequency is no more than +3 dBm.
The YTF filter performance is as follows:
Table 13-11 Passband Performance
Frequency Range (GHz)
Insertion Loss (dB)
Frequency Range (dB
insertion Loss with Temperature
(dB)
Iinput VSWR (max)
Output VSWR (max)
1 dB Compress dBm
IBandwidth min MHz
The rejection performance at 600 and 1200 MHz offsets referenced to
passband insertion loss is as follows:
13-34 HP 70427A/HP 70428A User's Guide
Band 1
2.4 to
2.75
7.5
) 5.0
p-p
±1.5
2.8:1
2.8:1
>10
25
Table 13-12 600 - 1200 MHz Offsets
2.4 to 18.0 GHz
Band 2 Band 3
2.75 to 13.0 to 20
13.0
6.5 6.5
5.0 5.0
±1.5 ±2.0
2.8:1 2.8:1
2.8:1 2.8:1
>10 >10
25 30
18.0 to 25.8 GHz
72 dBc 62 dBc
Band 4
20 to 25.8
6.5
5.0
±2.0
2.8:1
2.8:1
>10
35