Noise Limiter Circuit - Racal Instruments RA-117 User Manual

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