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Videotek DM-154 Frequency Agile Demodulator
The Videotek DM-154 demodulator is a high performance television tuner/demodulator which, in addition to being at home in basic broadcast, cable and closed circuit monitoring applications, can also be used for FCC compliance testing. It contains features beyond standard tuners, including forced mono mode, a Zero Carrier Pulse (chopper), 4.5 MHz aural carrier output, external IF loop and remote control via an RS-232 port. The DM-154 may be used in testing applications and in locations where computer control is required.
Features
- 154 channel tuning (VHF/UHF/Cable)
- HRC/IRC tuning capability via wide range fine tuning
- Random access, search or up/down channel selection
- Front panel Cable/Antenna selection
- Frequency synthesized channel selection
- Synchronous detection
- Stereo presence indicator
- Front panel LED channel display
- Controls for video gain, audio gain and balance on front panel
- Front panel memory retained for one week in event of power loss
- Full 4 MHz bandwidth video for compliance testing
- Quadrature output for ICPM measurements
- SAP presence indicator
- Front panel selection of Stereo, Mono or SAP outputs
- Zero Carrier Pulse control on front panel
- Remote control via an RS-232 port
- IF (45.75 MHz) loop enabled by an internal jumper
- Suitable for full FCC proof of performance testing
Specifications
| Tuner |
| Tuning Range |
55.25 MHz to 801.25 MHz |
| Connector |
"F" 75Ω, female |
| Input Range |
-15 to +15 dBmV |
| Maximum RF Input Level |
+30 dBmV |
| Cross Modulation |
<-50 dB nominal |
| Fine Tuning Range |
±2 MHz in 64 steps (62.5 kHz per step) |
| Frequency Stability |
±15 kHz typical |
| Channel Coverage |
VHF Channels 2-13 |
| UHF Channels 14-69 |
| Cable Channels 2-99 |
| Band Coverage |
Low, Mid, High, Super, UHF |
| Detector |
Synchronous |
| IF Loop |
+20 dBmV typical, internally enabled |
| Video |
| Video Outputs |
2 NTSC video outputs, sync negative 75 source terminated |
| Connectors |
BNC 75Ω, female |
| Level/td>
| 1V p-p, typical into 75Ω load |
| Adjustment Range |
±3 dB typical (front panel control) |
| Chroma/Luma Delay |
Within 30 ns typical (ref -170) |
| Differential Phase |
<4° |
| Frequency Response |
0.5 MHz to 3.6 MHz ±1 dB |
| Differential Gain |
<4% |
| Bandwidth |
0.5 MHz to 4.0 MHz ±1 dB (Trap out) |
| Signal To Noise Ratio |
>50 dB at 0 dBmV |
| Zero Carrier Output |
User selection ON/OFF; Location of Zero Carrier Pulse selectable from line 10 through line 25 via front panel |
| Quadrature Output |
within 7° |
| Audio |
| Audio Line Outputs |
Balanced stereo (left and right) |
| Connector |
"F" 75Ω, female |
| Level |
0 dBm, typical across 600Ω |
| Adjustment Range |
-16 dBm to +4 dBm |
| Frequency Response |
50 Hz to 12 kHz (stereo mode) |
| Signal To Noise Ratio |
50 dB at 0 dBm |
| Stereo Separation |
>20 dB @ 1 kHz |
| Distortion |
2% maximum, 1 kHz to 12 kHz |
| Audio Speaker |
Internal 1" speaker, front panel level control |
| 4.5 MHz Aural Output |
+10 dBmV or +34 ±2 dBmV selectable |
| Composite Audio Output |
110 kHz bandwidth, 0.5V p-p |
| Connector |
BNC 75Ω, female |
| Power |
| Input |
90 - 264 VAC, 50/60 Hz |
| Consumption |
35 VA, typical |
| Connection |
Detachable 3 wire power cord, per IEC 320 |
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