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Techanlogix TM150 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.
Standard Features:
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Selectable output
channels:
Standard Broadcast VHF, UHF,
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SAW filtered IF designed
for adjacent channel operation
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+ 60 dBmV output using
low distortion hybrid amplifiers
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Synthesized oscillators -
crystal referenced phase locked
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Modulation LED readout
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Surface mount technology
construction
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Phase lock loop FM audio
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BTSC stereo compatible
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External separate
audio/video and composite IF loop-through
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Aural carrier level
adjustable -10 dB to - 15 dB
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Video delay predistortion
network meets FCC 73.687
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High stability TCXO, +
250 Hz
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Non-volatile memory
retains channel selection after power loss
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RF
Characteristics |
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Frequency Range |
7 to
750 MHz |
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Frequency Response (one Channel) |
± 0.5
dB |
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Frequency Stability |
± 250
Hz |
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RF
Output Level |
60 dBmV
max |
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Harmonics |
>60 dB
below rated power |
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Predominant Intermodulation Products |
dBc =
decibels below visual carrier |
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+920kHz |
>60 dBc |
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-920kHz |
>60 dBc |
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+2.66
MHz |
>60 dBc |
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-2.66
MHz |
>60 dBc |
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+5.42
MHz |
>60 dBc |
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+7.16
MHz |
>60 dBc |
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3rd
Order Intermodulation Products |
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-4.5
MHz |
>60 dBc |
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+9.0
MHz |
>60 dBc |
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All
Others |
>60 dBc |
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Spurious Emissions |
>-60
dBc |
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NTSC
Video Characteristics |
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Input
Level (for 87.5% modulation) |
1.0
Vpp |
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Differential Phase (at 87.5% modulation) |
± 2
Degrees |
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Differential Gain (at 87.5% modulation) |
2 % |
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Group
Delay |
< ± 40
ns |
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K-Factor |
1.9%
for 2T Pulse |
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Hum and
Noise |
> 60 dB
below rated Power |
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Aural
Characteristics |
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Input:
50 Hz – 15 KHz |
0 dBm
(0.8V) |
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Impedance |
600
ohms, balanced |
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Frequency Response |
± 1 dB |
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Frequency Tolerance, ± 500 Hz |
4.5 MHz |
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Frequency Deviation |
± 25
KHz |
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Harmonic Distortion |
1% max |
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Preemphasis (mono) Internally Defeatable |
75ms |
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IF
Section |
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Output
Impedance |
75
ohms, unbalanced |
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Video
IF level |
+ 37
dBmV, +97 dBmV |
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Audio
IF level |
+ 22
dBmV, +82 dBmV |
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Return
Loss |
>14 dB |
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Video
Sound Spacing |
+ 4.5
MHz |
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Vestigial side-band width |
0.05
MHz |
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Second
IF Frequency |
945.75
MHz |
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