|
TM-200 Modulator
The high output
modulator eliminates the need for preamplifiers prior to the power
amplifier system. The modulator processes baseband audio and video
information to provide an IF output consisting of a visual IF
carrier at 45.75 MHz, using amplitude modulation, and an aural IF
carrier at 41.25 MHz, using frequency modulation. An internal
upconverter translates the modulator circuitry's IF carriers to VHF
and UHF television frequencies. All operating controls are located
on the front panel. An aural loop through is provided to properly
set transmitter power.
-
Totally microproccessor controlled with self-diagnostic
monitoring
-
SAW
filtered IF designed for adjacent channel operation
-
+ 10
dBm minimum output using low distortion hybrid
amplifiers
-
Synthesized oscillators - crystal referenced phase
locked
-
Bar
graph modulation and digital LED readout
-
Internal switch selects standard or HRC output
-
Surface mount technology construction
-
IF
Pre-Correction adjustment
-
Sync
level adjustment
-
Video
detection
|
-
RF
muted during tuning
-
Phase
lock loop FM audio
-
BTSC
stereo compatible
-
External separate audio/video and composite IF
loop-through
-
RS-232 control option (daisy-chain capable)
-
Aural
carrier level adjustable -10 dB to -15 dB
-
Video
delay pre-distortion network meets FCC 73.687
-
High
stability TCXO ± 250 Hz
-
Non-volatile memory retains channel selection after
power loss
-
DC
restoration
-
Video
detection
-
White
clip
|
|
RF
Characteristics |
|
Frequency
Range |
7 to 750
MHz |
|
Frequency
Response (one Channel) |
± 0.5 dB |
|
Frequency
Stability |
± 250 Hz |
|
RF Output
Level |
10 dBm
min |
|
Harmonics |
>60 dB
below rated power |
|
Predominant Intermodulation Products |
dBc =
decibels below visual carrier |
|
+920kHz |
>60 dBc |
|
-920kHz |
>60 dBc |
|
+2.66 MHz |
>60 dBc |
|
-2.66 MHz |
>60 dBc |
|
+5.42 MHz |
>60 dBc |
|
+7.16 MHz |
>60 dBc |
|
3rd
Order Intermodulation Products |
|
|
-4.5 MHz |
>60 dBc |
|
+9.0 MHz |
>60 dBc |
|
All
Others |
>60 dBc |
|
Spurious
Emissions |
>-60 dBc |
|
NTSC
Video Characteristics |
|
Input
Level (for 87.5% modulation) |
1.0
Vpp |
|
Differential Phase (at 87.5% modulation) |
± 2
Degrees |
|
Differential Gain (at 87.5% modulation) |
2 % |
|
Group
Delay |
< ± 40 ns |
|
K-Factor |
1.9% for
2T Pulse |
|
Hum and
Noise |
> 60 dB
below rated Power |
|
Aural
Characteristics |
|
Input: 50
Hz – 15 KHz |
0 dBm
(0.8V) |
|
Impedance |
600 ohms,
balanced |
|
Frequency
Response |
± 1 dB |
|
Frequency
Tolerance, ± 500 Hz |
4.5 MHz |
|
Frequency
Deviation |
± 25 KHz |
|
Harmonic
Distortion |
1% max |
|
Pre-emphasis (mono) internally defeatable |
75ms |
|
IF
Section |
|
Output
Impedance |
75 ohms,
unbalanced |
|
Video IF
level |
+ 37 dBmV,
+97 dBmV |
|
Audio IF
level |
+ 22 dBmV,
+82 dBmV |
|
Return
Loss |
>14 dB |
|
Video
Sound Spacing |
+ 4.5 MHz |
|
Vestigial
side-band width |
0.05 MHz |
|
Second IF
Frequency |
945.75
MHz |
|
Physical
Characteristics |
|
Power
Requirements |
110 / 220
Vac, 1 Aac at 110 Vac |
|
Dimensions |
W-19”,
D-16” w/connectors, H-2U |
|
