DRAKE VMM860AG Manual - Halaman 2
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Halaman Cetak
2
FRONT PANEL CONTROLS and INDICATORS
F1
F2
F3
F4
F5
F6
F7
F1 - POWER/ERROR Indicator
Lights when the unit is connected to the
required source of DC power via the rear panel
DC INPUT connector. A flashing condition
indicates an invalid channel setting or other
conditions that would cause the unit to operate
on an invalid channel. The RF output is
switched off for flashing (ERROR) conditions.
F2 - AUDIO Level Control
The setting of this screwdriver adjustment
determines the aural carrier deviation. Clock-
wise rotation increases the carrier deviation.
F3 - VIDEO Level Control
The setting of this screwdriver adjustment
determines the video modulation level.
Clockwise rotation increases the modulation
depth.
F4 - Channel Number Switch
Sets the desired operating channel for standard
CATV channels 02 through 135 or Broadcast
TV channels 02 through 69. See also Item F5
which sets the type of channel (CATV or
Broadcast TV) and sets the leading "1" for
CATV channels 100 through 135.
CAUTION: USE AN INSULATED SCREWDRIVER
BLADE WHEN ADJUSTING THE AUDIO, VIDEO,
A/V, OR RF ADJUSTMENTS.
THIS WILL PREVENT THE POSSIBILITY OF
SHORTING CIRCUITRY TO THE FRONT PANEL
IN THE EVENT THAT THE SCREWDRIVER
SLIPS OUT OF THE SLOT IN THE PLASTIC
SHAFT OF THE POTENTIOMETER.
VMM860AG
POWER/
ERROR
AUDIO
VIDEO
2
5
C A T V
CATV
B C
+100
T V
A / V
R F
Figure 1
F5 - Mode Switch
Sets the type of channel, CATV or Broadcast
TV ("BC TV"). The first position of the switch
("+100") sets a leading "1" for CATV channels
100 through 135. See also Item F4 for setting
the channel number.
For example:
For example:
Setting for CATV
Setting for CATV
channel "125"-
channel "25"-
2
5
CATV
BC
CATV
CATV
+100
TV
+100
F6 - A/V Ratio Control
This screwdriver adjustment varies the level of
the aural carrier over a range from 12 to
22 dB below the visual carrier. The aural carrier
should be adjusted to approximately 15 dB
below the visual carrier (normal operation).
Clockwise rotation increases the aural carrier
level.
F7 - RF Output Level
This screwdriver adjustment permits decreasing
the RF output level a minimum of 10 dB as the
control is rotated counterclockwise. Set the
control for a +45 dBmV output level .
FCC Frequency Offsets:
Intercarrier Frequency:
Spurious Outputs (5 MHz to 1 GHz):
Input Level for 87.5% Modulation:
Input Level for 25 kHz Peak Deviation:
2
5
CATV
BC
TV
Total Harmonic Distortion:
Operating Temperature:
RF
Frequency Range:
54 to 864 MHz;
Standard, HRC, or IRC CATV channels 2 to 135,
Broadcast TV channels 2 to 69.
Automatic (+12.5 kHz, +25 kHz, or none as required for each
channel).
Output level:
+45 dBmV minimum (10 dB adjustment range).
Output Impedance:
75 Ohms, 8 dB return loss.
A/V Ratio:
Audio carrier level, adjustable from -22 to -12 dB
referenced to video carrier level.
Frequency Stability:
Within ±5 kHz
4.5 MHz
-60 dBc, measured at -15 dB A/V ratio and with modulator
output level of +45 dBmV.
In-channel C/N:
65 dB typical, 4 MHz bandwidth.
Broadband Noise:
-78 dBc typicial, 4 MHz bandwidth @ +45 dBmV output.
VIDEO
0.65 Vp-p to 1.5 Vp-p. Manual gain adjust with
front panel control.
Input Impedance:
75 Ohms, return loss of 26 dB minimum.
Frequency Response:
20 Hz to 4.2 MHz, ±1 dB.
C/L Delay:
Within 50 nSec. of 0 nSec. (standard), or
FCC predistortion, (option).
Differential Gain:
3% maximum (10 to 90% APL).
0
Differential Phase:
3
maximum (10 to 90% APL).
AUDIO
125 mV rms to 2.5 V rms. Manual gain adjust with
front panel control.
Input Impedance:
Greater than 10 K Ohms, unbalanced.
Pre-emphasis:
75 Sec. normal, defeatable (flat) by rear panel switch for
BTSC baseband stereo compatibility.
Frequency Response:
40 Hz to 15 kHz, ±1.0 dB referenced to 75 Sec.
pre-emphasis curve.
40 Hz to 100 kHz, ±0.5 dB if pre-emphasis is defeated.
S/N ratio:
65dB.
1% maximum.
GENERAL
DC Power Input:
+12 V ±5% at 200 mA
+5 V ±5% at 350 mA
0
0
0
C to +50
C ambient.
Size:
1" W x 3.5" H x 7.5" D. (2.5 cm) W x (8.9 cm) H x (19.1 cm) D.
Weight:
10.7 oz. (0.3 Kg).
Specifications subject to change without notice or obligation.
SPECIFICATIONS
7