Westinghouse Type KR, Инструкция по установке и эксплуатации

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I.L. 4 1-94 1A
TAB L E 5
TYPICAL RF SIGNAL M EASU R EM ENTS FOR TRANSMI TTER
CHECK P O I N T
T5- 1 to Gnd.
T5-3 to Gnd.
J 13 to Gnd.
Q 10-C to Gnd.
T6- 2 to Gnd.
Q 1 2-B to Gnd.
Q 1 5-B to Gnd.
Q 1 2-C to Gnd.
Q 15-C to Gnd.
T7-5 to Gnd.
Output to Gnd.
A P P L I C A T I O N
1.
Receiver Selectivity (Fig. 1 1)
This shows a typical curv e of the overall
selecti.vity of the receiver under steady state
conditions.
2. Transmitter Output Selectivity ( Fig. 8)
Typical curv es are shown so that approximate
bandwidths for keying purposes can be determined for
any carrier frequency b etween 30-kc and 200-kc.
3. Minimum Channel Spacing ( Fig. 13)
This is a graph from which minimum channel
spacing can be obtained provided the signal strength
of the interfering transmitter and the sensitivity set­
ting of the receiver are known. These can be obtained
from c alculations or by m easurements.
For example, if the interfering transmitter volt­
age is measured ( at the receiver) and found to be 2. 5
VOL T S
5. 5
1.0
0.085
6.0
6.0
0.8
0 . 8
38 .0
38.0
9 . 8
8.0
volts, this would be 10-db down from 8 volts. This
point can be located on the right hand column of the
graph. Then, if the receiver sensitivity were set to
operate on 0 . 8 volts or 20-db, this point would be
located on the left hand column. A line could then be
drawn through the two points as shown by the dotted
line. The intersection .of this line with the center
line indicates the m inimum channel spacing. In this
case if the interfering signal is being keyed on-off, at
15 pps, the minimum spacing would be 2. 5-kc,
4. Transmitter Output and Receiver Sensitivity
Variations with Voltage ( Fig, 10)
The se curves show the variation of transmitter
output and receiver sensitivity with changes in supply
voltage, at 120-kc and 25°C, The increase and de­
crease in
transmitter
output above or below 1 . 0 watts
may be obtained in db from the transmitter curve.
1 . 0 watts is about 8.0 volts with a 60-ohm load.
The increase and decrease in receiver sensi­
tivity above or below 40 millivolts can similarly be
1 3
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