Technical Specification
5
Bandwidths 5 and 6 are obtained with crystal-lattice fil-
ters; differences in centre frequencies of these bandwitdth
settings do not exceed 50c/s.
I.F. Output:
100 kc/s at 75-ohms impedance. Level 0.2 V approx, with
A.V.C. in operation. Two outlets in parallel are provided.
Image and Spurious Responses: With wideband or tuned input, external image signals
are at least 60dB down. Internally generated spurious re-
sponses are less than 2dB above noise level in all cases.
Noise Factor:
Better than 7dB throughout entire range.
B.F.O. Range:
±
8 kc/s
B.F.O. Stability:
With constant ambient temperature and supply voltage,
drift after warm-up does not exceed 50 c/s. For input level
variations from 10
µ
V to 1mV, B.F.O. drift is negligible.
Automatic Volume Control:
An increase in signal level of 20dB above 1
µ
V improves
the signal-to-noise ratio by 18dB. An increase in signal
level of 100dB above 1
µ
V increases the A.F. output by
less than 7dB.
A.V.C. Time Constants:
Short:
Charge
25 milliseconds
Discharge
200 milliseconds
Long:
Charge
200 milliseconds
Discharge
1
second
A.F. Response:
With 13 kc/s bandwidth, response remains within
±
4dB
from 250 c/s to 600 c/s.
A.F. Output:
1. 2.5-in. loudspeaker on front panel (switched).
2. Two headphone sockets in parallel on front panel.
(see Note)
3. Three independent outputs of 3mW at 600-ohms
at rear of chassis.
4. One output of 10mW at 600-ohms. Preset level
is independent of A.F.GAIN control setting.
5. One output of 1W at 3-ohms. Note: The two
headphone sockets are connected across one of
the 600-ohms, 3mW outlets.
Distortion:
Not greater than 5% at 1W output.
Hum Level:
With A.F.GAIN control at maximum, the hum level is
never worse than 40dB below rated output (1W)
Noise Limiter:
A series noise limiter circuit van be switched into oper-
ation to provide limiting at modulation levels exceeding
30%.
Meter Indication:
Alternative switching for indication of signal carrier level,
A.F. output level or ”S” meter indication.
Power Supply:
100-125V and 200-250V, 45-65 c/s. Power consumption
100W approx.
Summary of Contents for RA-117
Page 1: ...Racal RA 117 Radio Receiver...
Page 24: ...Detailed Circuit Description 24 at maximum is the correct calibration maintained...
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