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PDI-50121AMS 860MHz SAW Filtered 134 Channel 50dBmV Frequency Agile Mini Stereo Modulator

Specifications and Documentation

The PDI-50121AM consists of 12 individual, vertically mounted, frequency agile modulators and an efficient switching type power supply module mounted in one 3-1/2” high housing. It is designed for 19” rack mounting. Each modulator is SAW filtered and is factory set to the desired channel and proper offset. Recessed front panel controls are preset, at the factory, for 87.5% depth of modulation, ±25kHz audio deviation, and - 15dBc video audio ratio. RF is set at maximum. It offers excellent video performance and high reliability in a 2U rack. This exceptional unit is manufactured and tested to the highest standards and complies with all FCC requirements.


• +45dBmV RF output level 
• Microprocessor Up/Down button channel selector
• Channel range of 2 to 134 (incl. A-5 to A-1)
• SAW filtering for true adjacent channel operation
• Heavy duty cast housing
• BTSC stereo compatible
• >-60dB spurious performance
• Compatible with competitors 12 in 1 modulator systems


Output Channels UP/DOWN Selectable 2 Through 134 including A-5 to A-1 (95-99).
Output Level +45dB Range
Output Level Adjustment 20dB Range
Spurious Output At least 60dB Below Video Carrier (@ +60dBmV Output With Aural Carrier 15dB Down)
Broadband Noise 80dB Below Video Carrier (@ +60dBmV Output)
Frequency Stability ±5kHz Maximum (±3kHz typical)
Vestigial Sideband Response -20dB at IF Channel Edge; -60dB at Adjacent Video and Aural Carrier Frequencies and Frequencies Further Removed


Input Type Composite Video, Negative Sync.
Input Level 0.5 Vp-p Min. for 87.5% Depth of Modulation
Frequency Response +0.75dB (10Hz to 4.2MHz)
Differential Gain 3% Typical at 87.5% Modulation
Differential Phase < 3° Typical at 87.5% Modulation
Hum And Noise -60dB Min. at 87.5% Modulation
Tilt 1.1% Maximum on 60Hz, 50% Square Wave
Group Delay Response Meets FCC Distortion Requirements for Color Transmission


Input Type RCA Unbalanced (Balanced Optional)
Input Impedance High Z
Input Level 250mV Min. for 25kHz Deviation
Frequency Response Mono ±0.75dB (30Hz to 20kHz)
Intercarrier Frequency 4.5MHz ±100Hz


AC Line and Power 90 - 240 Vac, 50/60Hz, 48 Watts
Operational Temperature 0 to 50 Degrees C
Rear Panel Connections:

  • RF Output F female 
  • Video Input F female 
  • Audio Input RCA 

Front Panel Controls:

  • UP/DOWN 
  • Channel Select 
  • CATV/UHF/HRC Mode Select (SET) 
  • RF Output Level 
  • Aural Carrier Level 
  • Video Modulation Depth 
  • Audio Deviation 

Front Panel Indicators:

  • Power On LED 
  • 2 Digit Channel Number 
  • +100 Range LED

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