GENERAL RADIO COMPANY 1263-8 Operating Instructions Manual page 9

GENERAL RADIO COMPANY
1.3 ASSOCIATED EQUIPMENT.
1.3.1 UNIT OSCILLATOR.
The following
is
a list of recommended Gen-
eral Radio Unit Oscillators:
Type No.
1211-B*
1215-B
1209-BL
1209-B
1361-A
1218-A**
Frequency Range
0.5 to 5 Me; 5 to 50 Me
50 to 250 Me
180 to 600 Me
250 to 920 Me
450 to 1050 Me
900 to 2000 Me
An earlier "A" model of the Type 1211, 1215, or 1209 Unit Oscil-
lator will operate satisfactorily with the Type 1263-B Amplitude-Regu-
lating Power Supply if the telephone plug
is
removed from the modulation
cable or
is
adapted to connect to the screw-terminals on the oscillator.
Types 1208-A and -B Unit Oscillators cannot be used with the Type
1263-B Amplitude-Regulating Power Supply. Other oscillators with suit-
able power requirements can be operated from this power supply if a de
connection can be made to the cathode circuit to apply plate-current control.
1.3.2 OUTPUT RECTIFIER.
The General RadioType 874-VR Voltmeter
Rectifier
is
recommended for use as the output rectifier over the frequency
range of 0.5 to 2000 Me. It can be plugged directly into the output con-
nector of General Radio Unit Oscillators, and provides a matched source
for 50-ohm coaxial cable. The backresistance of the crystaldiode should
exceed 40,000 ohms. The ripple in the output of the rectifier must be less
than 10 percent at frequencies above 0. 5 Me to prevent overloading the con-
trol amplifier; this condition
is
satisfied when a Type 874-VR with a good
crystal diode is used. With the Type 874-VR Voltmeter Rectifier, there-
sponse time is essentially determined by the internal compensation in the
power supply. The stability of the control system (freedom from hunting
and oscillation)
is
established by this compensation.
1.3.3 OUTPUT FILTER.
To minimize errors due to oscillator harmon-
ics, a low-pass filter can be used between the oscillator output and the
output rectifier (refer to Section 5). The following General Radio filters
are recommended:
Type 87 4- F 185
Type 87 4-F 500
Type 874-F1000
Type 874-F2000
• Not recommended for modulated operation •
185-Mc Low-Pass Filter
500-Mc Low-Pass Filter
1000-Mc Low-Pass Filter
2000-Mc Low-Pass Filter
.. For both cw and square-wave modulated operation with the Type 1263-B, set the Type
1218-A selector switch to CW.
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