The 222 was originally developed as a "post-processor" to ensure US broadcasters' compliance with FCC-mandated occupied-bandwidth regulations. It incorporates a fast, asymmetrical peak limiter, independent pre-emphasis-protection limiting, and a very sharp-cutoff low-pass filter with proprietary overshoot control.
The 222 finds ready application in a wide variety of AM broadcast situations. In addition to the NRSC 10kHz cutoff for medium-wave AM broadcasting in the US, any high-frequency protection characteristic between 4.5kHz and 15kHz can readily be accommodated to meet other domestic and overseas needs. Though the 222 is intended to provide basic final limiting, a "floating platform" release characteristic yields sufficient program dynamics compression that often the unit can be run "barefoot" between the console and transmitter with good results. (PWM) control.
• The built-in Peak Controller can enhance or replace existing limiters to maintain the asymmetrical AM modulation advantage.
• A separate pre-emphasis protection limiter independently controls high frequency program energy for best utilization of the NRSC (or other) transmission characteristic.
Feedforward pulse-width-modulation (PWM) techniques are utilized in limiter and adaptive pre-emphasis stages for colorless, quasi-digital control of the program signal.
• Active multipole low-pass filtering exceeds requirements for adjacent-channel protection, even under adverse conditions. A proprietary overshoot compensator eliminates any need for splattergenerating clippers to assure full modulation.
"PROOF" mode: 0.5dB, 10Hz-15kHz
222-00 (NRSC): 1dB, 10Hz-9.7kHz
222-01 (Euro MW): 1dB, 10Hz-8.7kHz
222-02 (US SW): 1dB, 10Hz-6.2kHz
222-03 (Int'l SW): 1dB, 10Hz-4.85kHz
•DISTORTION: Less than 0.2% THD, 10Hz cutoff with Peak Limiter OFF. Less than 1% THD, 200Hz cutoff with Peak Limiter ON.
•NOISE: Better than 75dB below full carrier modulation (assuming NRSC de-emphasis).
•FIXED PRE-EMPHASIS: The US version follows the œtruncated 75 curve specified by the NRSC transmission standard. Alternative versions employ pre-emphasis appropriate to the service and the cutoff frequency.
•INPUT: Active-balanced, bridging; accepts nominal program line levels between 15dBu and +15dBu.
•OUTPUT: Active-balanced, 600-ohm resistive source; delivers 0dBm to +15dBm into 600 ohms.
•OUTPUT ASYMMETRY: Positive peak amplitude is continuously variable between +100% and +130% of the negative peak value.
•POWER REQUIREMENTS: 105-130VAC and 210-260VAC; 50/60Hz; 20W.
•SIZE AND SHIPPING WEIGHT:23 x 16x2 (2U); 8 lbs/584mm
; 3.6 kg