EIP 545A - Page 33

The
L.O. frequencies
being used, except the range of direct counting
(< 190 MHz), have been selected
so only IF frequencies from
25 MHz to 185 MHz are required. Since the counter can count signals less
than
10 MHz, the restricted operating range provides margin for frequency modulation on the input
signal, and for incrementing the
VCO frequency.
Figure
4-4 shows the operating ranges for the various harmonics and VCO frequencies used.
Figure
4-4.
Band 2 Operating Ranges
Input
Frequency
Range
FIN(MHz)
10- 190
185
- 345
345
- 400
400
- 560
560
- 610
610- 725
725
- 825
825- 935
935
- 1035
1035
- 1164.8
VCO
Frequency
Fvco(MHz)
-
370
425
375
425
375
425
375
425
489.9
Harmonic
Number
N
0
1
1
1
1
2
2
2
2
2
IF
Frequency
Range
FIF(MHz)
10- 190
.I85 - 25
80- 25
25
- 185
135
- 185
140
- 25
125- 25
75
- 185
85- 185
55.2
- 185
Scans by ArtekMedia © 2007