718 - David III FM Broadcast Processor

THIS PRODUCT IS NO LONGER IN PRODUCTION

The 718 "DAVID-III" combines comprehensive multiband audio processing with a digital-synthesis stereo generator for unparalleled performance and great value. Pulse-width-modulation (PWM) techniques ensure rock-stable operation and a very competitive, yet effortless sound. Density and equalization adjustments allow the broadcaster to tailor the 'signature' of the on-air sound. Proprietary PIPP* final limiting and an adjustable composite clipper guarantee full carrier modulation for any program audio source or characteristic.

Features


  • THIS PRODUCT IS NO LONGER IN PRODUCTION

  • Third-generation DAVID processing

  • FM processor/generator

  • Easy to install and use without the need for external test equipment

  • 3-band feed forward Pulse-Width-Modulation (PWM)

  • Gated-AGC (Automatic Gain Control)

  • PIPP (Polarity Independent Peak Processing) limiter and a built-in adjustable composite clipper

  • Digital synthesis of the multiplex baseband signal

Product Image

Specifications


Frequency Response

±0.5dB, 20Hz-15kHz

Stereo Separation

55dB, 50Hz-15kHz (typically 60-70dB)

Noise

Better than 70dB below 100% modulation in decoded L/R audio. Individual digital noise components above 54kHz are –70dB or better.

Distortion

<0.5%THD in baseband and subcarrier at 95% modulation with PIPP* limiter defeated; <1.5% at any level of modulation with PIPP* limiter engaged.

Crosstalk (M/S or S/M)

Nonlinear crosstalk is better than –50dB, 50Hz-15kHz. Linear crosstalk (through processing and filters) is better than –40dB.

Pre-Emphasis

75μs or 50μs selected by internal jumpers.

PIPP* Limiter

(*Polarity Independent Peak Processing) Proprietary circuitry assures full carrier deviation by program audio regardless of signal asymmetry. The limiter may be defeated with a front-panel switch.

Low-Pass Filtering

The 7-pole, phase-corrected, active-elliptic LPF includes proprietary overshoot compensation.

Composite Clipper

Baseband clipping may be adjusted between 0dB and 3dB. Clipping is performed prior to pilot injection.

Stereo Pilot

19kHz, ±1Hz. Pilot is adjustable between 6% and 12% relative to 100% modulation.

Digital Synthesis Sampling Rate

608kHz (16X subcarrier oversampling)

Composite Output

The 75-ohm, unbalanced BNC output is variable between 1V p-p and 10V p-p with reference to 100% carrier modulation.

Power Requirements

105-130VAC and 210-260VAC; 50/60Hz; 20W.

Size and Weight

23” x 16” x 2” (2U); 8 lbs

584mm x 406mm x 51mm ; 3.6 kg