2
6
7
2.2d
Reference Oscillator:
Schematic Diagram 10368037/Rev B
t
A2A2A2
10MHz REF. OUT (J1, J2)
3.5V P/P square wave
Frequency Stability
0.3ppm /
30
(
C to +60
(
C
Current Draw
15mA @ +5V
The Reference Oscillator provides a high stability 10MHz signal which provides accuracy and long-
term frequency stability for the UHF Synthesizer (A2A2A1). This reference module is centered
around a 10MHz temperature-compensated crystal oscillator (G1) using 5V as power. The output
from G1 is buffered by two exclusive-OR gates used as inverters. The output signal from each
gate is a 10MHz low-level square wave with a frequency stability of 0.3 parts per million (ppm).
2.2e
UHF Bandpass Filter:
Schematic Diagram 20404015/Rev 51
t
A2FL1
INPUT (J1)
10 to
18dBm
OUTPUT (J2)
0 to
8dBm
Bandwidth (J1-J2)
8MHz to 15MHz @ 1dB
Gain (J1-J2)
10dB
Current Draw
50mA @ +5V
The UHF Bandpass Filter is a six-section comb-line design joined with a single-stage amplifier to
provide 10dB of total module gain. The first three sections of the filter, composed of variable
capacitors C1/C2/C3 and their associated tuned stubs, are terminated at the input of U1, a 14dB
amplifier. Variable capacitors C1/C2/C3 and C4/C5/C6 electrically lengthen or shorten their
connected stubs to pass the chosen UHF channel with the appropriate coupling provided by
spacing between the stubs. For extra stub length at lower frequencies, capacitors C7/C8/C9/C10/
C11/C12 are added to operate at channels below 560MHz. The bias for U1 is obtained from the
5 volt power supply via R1 and RF choke FB1 (ferrite bead) with bypassing furnished by capacitors
C15/C16/C17. Loading wires W1/W2/W3/W4 set the input and output impedance of each three-
section filter segment, dictating the overall bandwidth and loss of the circuits. FL1 is tuned to
select the desired UHF mixer products from the lower sideband, or difference signal, found at the
RF OUTPUT of the IF/Converter (A2PC1).
2.2f
2W UHF Amplifier:
Schematic Diagram 30404029/Rev 54
t
A2A1
INPUT (J1)
0 to
8dBm peak visual
OUTPUT (J2)
+22dBm peak visual
Gain (J1-J2)
20dB to 38dB manual set
Frequency Response (J1-2)
±1dB/470-806MHz
Current Draw
500mA @ +28V
210mA @ +15V