DRAKE VM2551 Manual de instrucciones - Página 7
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RF
Frequency Range:
82 CATV channels, 54-550 MHz:
channels 2-78 and 95-99, and
Off-air broadcast channels 2-27.
FCC Frequency
Offsets:
Automatic: Zero, +12.5 kHz, or
+25 kHz offset, for aeronautical
channels.
Output Level:
+55 dBmV minimum, (typically
adjustable from +40 to
+55 dBmV).
Output Impedance:
75 OHMS, return loss of 12 dB,
nominal.
A/V Ratio:
Audio Carrier -18 to -12 dB
referenced to video carrier,
adjustable.
Frequency Stability,
Visual:
Within ±5 kHz (FCC offset CH).
Within ±10 kHz (other CH)
Aural Intercarrier
Frequency:
4.5 MHz, ±2 kHz.
Spurious Outputs:
-60 dBc minimum, measured
at -15 dB A/V ratio and with
modulator output level of
+55 dBmV.
In-Channel C/N:
62 dB typical, 60 dB minimum.
Broadband Noise:
-75 dBc typical @ ±12 MHz or
greater spacings. (Specified
levels are referenced to the video
carrier and measured in a
4 MHz bandwidth).
VIDEO
Input level for 87.5%:
1 Vp-p ±3 dB, manual
gain adjust with front
panel control and
overmodulation indicator.
Input Impedance:
75 Ohms.
Frequency Response:
Flat ±1.5 dB from 30 Hz to
4.2 MHz.
Video S/N:
60 dB, luminance weighted.
L/C Delay:
Within 50 nSec of FCC
predistortion (complies with
FCC rules, 76.605).
Differential Gain:
Less than ±5%
(10 to 90% APL).
Differential Phase:
Less than ±5 degrees
(10 to 90% APL).
Specifications
AUDIO
Input Level for 25 kHz
Peak Deviation
@ 1 kHz Tone:
175 mV rms minimum. 250 mV
rms nominal. Manual gain
adjustment with front panel
control and overmodulation
indicator.
Input Impedance:
10K Ohms, unbalanced.
Pre-emphasis:
75 Sec.
Frequency Response:
40 Hz to 15 kHz, ±1.5 dB,
referenced to 75 Sec
pre-emphasis curve.
Total Harmonic
Distortion:
1.5% maximum.
Hum and Noise:
-60 dB minimum, referenced
to 25 kHz peak deviation.
4.5 MHz INPUT
(Internal Jumper
Change to Activate)
Input Level:
37 dBmV for -15 dB A/V ratio.
COMPOSITE IF
LOOP
IF Frequency:
45.75 MHz visual carrier,
41.25 MHz aural carrier. Loop
output is after SAW filtering.
Loop Level:
40 dBmV (visual carrier).
Loop Impedance:
75 Ohms.
GENERAL
AC Power Input:
115 VAC ±10%, 60 Hz,
25 WATTS.
Operating Temperature
0
Range:
0
Size:
19" W x 1.75" H x 11.8" D.
Weight:
9 Lbs., 4 oz.
Connectors:
Video input, IF loop, 4.5 MHz In
and RF output are all type F.
Audio input is RCA phono.
7
0
C to +50
C, ambient.