I
I
I
I
I
I
I
I
I
I
l
show the relationship of the received signal to the local oscil
lator frequency.
In the FSK mode (SSB), the crystal frequency
is 9 MHz above the carrier frequency on bands A, B, C, and L
and 9 MHz below the carrier on bands D and E.
In the
AM
mode the crystal frequency is 9001.4 kHz above
the carrier on bands A, B, C, and L and 8998.6 kHz below the
carrier on bands D and E. The crystal is 1.4 kHz above the FSK
crystal frequency in order to center the audio channel (300 to
3000 Hz) in the IF crystal filter band-pass.
Table 3-2.
Signal Frequency vs. Crystal Frequency
BAND
FREQUENCY
CRYSTAL
RANGE
RANGE MHz
(+1.4 kHz for
AM)
A
1. 7 MHz - 3. 5 MHz
10.7 - 12.5
B
3. 5 MHZ - 7 MHZ
12.5 - 16
c
7 MHZ - 13 MHZ
16 - 22
(excluding 9
MHz. IF Channel)
D
13 MHz - 20 MHz
4 - 11
E
20 MHZ - 29 MHZ
11 - 20
L
10 )1Hz - 550 kHz
9.010 - 9.550
-
Table 3-3 lists certain frequencies that cannot be received
by the Model 1500B because of spurious interference.
Crystals
used should meet the following specifications:
Mode of oscillation:
4,000-22,000 kHz, AT cut
Shunt capacitance:
7 Pf (maximum)
Resistance:
75 to 25 ohms
Maximum drive:
10 milliwatts (4,000-9,999 kHz)
4 milliwatts ( 10,000-22,000 kHz)
Load capacity:
32 Pf
0
0
Temperature Tolerance:
-10
to +60
C within 0.0005%
Holder:
HC6/U
3.2.8
OSC TRIM CONTROL
The OSC TRIM control permits the frequency of the crystal
local oscillator to be varied slightly around its center frequency
for optimum tuning of the received signal.
(Recall that each
3-5
Summary of Contents for lSOOB1500B
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