High Definition for Europe  (11p ENG)	Hellas SAT2 satellite handbook  (87p ENG)
Summary characteristics of the HOT BIRD sat.  (35p ENG)	Hellas SAT2 satellite User's manual  (15p ENG)
Annex_a_HOTBIRD_sat_system  (18p ENG)
EUTELSAT Systems Operations Guide (109p ENG)
EUTELSAT Television Handbook (47p ENG)

 

Audio Levels	In the early days of broadcasting, most programming was live, equipment was unreliable and budgets were generous. Often, a trained engineer was at the controls at all times mainly to "ride gain" and insure that that audio levels were consistent. The measurement tools included ears and a large VU meter. However, this manual process was fraught with inconsistency, especially as FCC operator requirements were relaxed and less-trained personnel were expected to perform additional tasks. To make matters worse, some managers and advertising producers wanted their station or commercial to stand out as the loudest, such as the infamous "Hey Culligan Man!" water softener ad.   Loudness Wars Over time, consumers became so irate at level inconsistency that hearings were held in Congress. In response, the FCC applied pressure to broadcasters who in turn increased their reliance on modulation monitors and audio limiters to stay legal while maximizing loudness. With great precision, modulation monitors display modulation on a meter as a percentage of the limit and via a "peak flasher" to show peaks the meter does not catch. "Staying legal" is as simple as keeping the light from flashing. Some monitors even provide a numeric count of how many times the limit has been exceeded. Early broadcast audio limiters did a poor job of controlling level - only marginally insuring compliance with regulations and at the same time introducing a variety of annoying "pumping" and distortion artifacts. Modern broadcast limiters are much improved and include a compressor function to prevent levels from going too low where they would become "buried in the noise". These limiters do a much better job of assuring legal audio with minimum artifacts while providing as much "presence" as possible. Casual measurements of nine stations in a large market show peak audio levels within 4 dB over a short time frame - a reasonable deviation.   Cable Audio Levels While the cable television industry can count on broadcast channels to have fairly uniform control over excessive modulation, the same cannot be said for the hundreds of satellite channels available for carriage. To avoid consumer complaint, some cable systems pass all analog channels through audio compressor/limiters in the cable head-end.   The Pre-Emphasis Problem The FM modulation system used for analog radio and television has a natural excess of noise at higher frequencies. To reduce this annoyance, designers of the FM modulation system for broadcasting decided to boost high frequencies before modulation (pre-emphasis) and reduce them in each receiver after demodulation (de-emphasis). They considered this a good solution; since programming of the day had little high frequency content, boosting it would not be a problem. However, microphones used today for audio capture have radically better high-frequency performance. Synthesized sounds with ample high-frequency content are commonplace. To compensate, broadcast limiters include "pre-emphasis protection", where loud high frequency sounds are limited more dramatically than low frequency sounds. The result is legal but unsatisfactory - loud sounds tend to sound "dull" and void of high-frequencies.   Peak Modulation is Not Loudness While broadcasters apply strict control over excessive modulation, this does not result in uniform loudness. Human hearing does not judge loudness the same way a modulation monitor reads percent modulation. Our ears are most sensitive to sounds in the frequency range of speech intelligibility - a natural design consistent with our need to communicate verbally. The ear also senses an average of dialog level over time. In the early days of "loudness wars", CBS Labs developed a "Loudness Meter" designed to mimic human loudness sensitivity. However, it's complexity-induced high cost and lack of incentive resulted in few being purchased by broadcasters. The proper use of a loudness meter to control audio levels would require that some programming be reduced in level so that their loudness match other programming of equal modulation but lower loudness. But many broadcasters prefer that modulation is maximized. They are happy if one program ends up sounding louder than others by leaving it at full modulation.   The Dynamic Range Problem While typical measures used for broadcasting assure a reasonable consistency in loudness levels for the consumer, there is a regrettable side effect. In these analog systems, there is no way to keep dialog consistent, remain legal, keep the noise low, and still provide consumers with the kind of symphonic sforzando or theatric explosion common in CDs and DVDs. Instead, these dramatic events are reduced to a same volume as speech.
Audio Limiters	Thanks to Xenofon from http://www.261.gr FM Audio Processing Today All Brands Are Trade Marks Registered To Their Owners Obsolete Products About Link Orban Optimod 8200S Too close on 8100A1/XT2 Discontinuedreplaced by 8300 or latest 5300 Multiband process, 2 or 5 band DSPV3.0. With stereo coder. This is the first digital fm   audio processor. Details Orban Optimod 2200 Discontinued replaced by 2300 2band processor, stereo encoder. Details Modulation Sciences  MYB-2Stereo Maxx Discontinued Stereo Spatial Enhancer plus diffusion. This is the first for broadcast use enhance stereo unit from early 80's with the unigue way of Mr. Eric Small.    Current Products About Link Orban Optimod 8500 New Upgraded version of 8400HD Multiple audio processing structures, 2 or 5 band DSP target zone gating AGC, stereo coder, 222A spatial, 42 new presets, intelligent clipping, composite limiting. Details RW Online Review Orban Optimod 5300  New Upgraded version of 8300? Multiband process, 2 or 5 band DSP derived stereo coder, target zone gating AGC, HF enhancer, 222A spatial, composite limiting. Details Orban Optimod 8400HD Parallel processing paths in one box, for curent Fm radio and for  iBiquity's HD Radio, Eureka 147 or Netcasting. Multiple audio processing structures, 2 or 5 band DSP target zone gating AGC, stereo coder, 222A spatial,more than  20 presets, intelligent clipping, composite limiting. Details Orban Optimod 8400S New Upgraded version of 8400 Multiband process, 2 or 5 band  DSP. With stereo coder,222A spatial enchancer, stereo maxx.  Details Orban Optimod 8400 Too far from 8200 Multiband process, 2 or 5 band  DSP. With stereo coder,222A spatial enchancer, stereo maxx.  Details Orban Optimod 8300 Just an low-priced 8400 The replacment of 8200 with new Multiband process, 2 or 5 band With stereo coder. Details Aphex   2020 MkIII  Analog Hi Sonic Perfomance Optical Pre-Emphasis Limiter Overshoot Compensated  Lowpass Filters, Baseband  Spectral Purity, Multiband Compression Algorithm. Optional stereo encoder. Details  IDT Dvp Fm From France. Multiband AGC, FFT Process Stereo Coder, Plug In  modular architecture. Details Solidyne 262-X From Argentina The flagship model.The only one with 7 bands on the market variable architecture, stereo enhancer, aural exciter.etc Low cost, a serious competitor of well known best selling processors. Optional stereo encoder. Details  Omnia 6fm 6-band digital processor stereo encoder, adjustable crossover, SPACE-EFX  stereo enhancement. Details Inovonics Omega fm 4Band process, with triple parametric EQ, split-spectrum final limiting, multi-band leveling, stereo coder. Details RW Online Review Solidyne Orion 462 From Argentina. 4 band with all the same principles of flagship 262X Optional stereo encoder. Details Junger D07 From Germany Adaptive pre-emphasis, adaptive spectral processing. Details Broadcast Technology Ultramod fm Ultra-transparent split band  Compressor-Expander, Dual composite outputs, Composite processing, Stereo generation Constant phase low pass filters. Details Warsanis 1401fm  From  Netherlands. 4 band programmable Audio Processor, Phase Rotator  Multiband clipper module.15kHz Low Pass Filter,  stereo coder. Details Orban Optimod 2300   New The replacment of 2200 with new feature like, Parametric EQ, 222A stereo spatial, high freq enhance "half-cosine" composite limiter.  Details CRLsystems Amigo fm Wide range dual-band AGC  multiband limiting, stereo encoder  stereo sound enhancement. Details Broadcastwarehouse DSP X The lower price. Multi band look ahead limiting adaptive bass and brightness plug-ins, adjustable parametric equalizers, stereo coder, with anti aliased composite clipper. Details RW Online Review Audemat - Aztec Fmx 410 & 480 The best at low price, All in one  sound processor, digital stereo generator, RDS encoder, DARC encoder and digital composite clipper. Using DSP technology. Details Solidyne 362 From Argentina. 3 band just the little sister of 262 & 462, analogue high end sound, super modulation with stereo encoder, low price. Details Tx Techniques UK All in one box lower price. TX-FM1/S/R/A 30W Stereo FM Exciter/Transmitter with integral RDS Encoder, Stereo 5-band Audio Processor and DTMF remote. Details Tiesecci Digimod 9500 Italian replica of Orban 8200? 6 Band Digital Processor  Dynamic Bass Manager  Pure Anti-Aliased clippers Built-In digital stereo encoder  Details Aev   Xtreme From Italy 5-band digital processor digital stereo encoder. FM AM, TV versions. Details Aev Diamond From Italy 3 band processor, digital stereo encoder, RDS, stereo enhancer. Details Aev Mirage MKIIFrom Italy 3 band processor, digital stereo encoder, all ajustable parameters Details Axeldigital Falcon 15 & 35  From Italy 5 & 3 Band Processor Digital stereo encoder Digital RDS coder. Details Orban Optimod Pc1100 For digital broadcast or webcast  No pre-emphasis, no stereo  coder, Multiband AGC and compression, equalization fine  tune "look-ahead" limiting over 20 factory presets, On board DSP minimizes CPU load.  Details TCelectronic DBMax 5 bandprocessor,Static Stereo Enhancement, Dynamic Static Eq No stereo coder. Details Translantech Ariane Sequel Successfully Analogue Ariane go to Digital Sequel. No stereo coder,  Details Translantech Ariane  The most fabulous pre-processor ever made Multi-Band RMS Processor Control the stereo sub-carrier modulation, matrix control circuit bass Humper circuitry. No stereo coder,  Details1 Details 2 Aphex Dominator II® Studio 720 & On air 722 Analog Hi Sonic Perfomance Transmission limiter Switchable pre/de-emphasis  3 Bands Limiting, Switchable Crossover Frequencies,  No srereo coder. Details Aphex Compellor ®320A Analog Hi Sonic Perfomance Compressor/Leveler/Limiter Intelligent compressor action leveling and peak limiting simultaneously. The ultimate Hi Quality Level Tool.  Details Aphex Aural Exciter® Type III 250 Just the first and best  exciter in the world. Details TCelectronic Finalizer Multiband Compressor Dynamic EQ,Stereo Adjust Spectral Stereo Image No srereo coder. Details Behringer PRO DSP9024 Digital 6 band Compressor Limiter, Gate, Peak Limiter No stereo coder. Details Behringer DSP1400P 2-Band Loudness Maximizer  Surroundprocessor  Noise reduction system. No stereo coder. Details Modulation Sciences CP-803 Composite Audio Processor First industry standard baseband processor, eliminates overshoots  Does not clip the 19 kHz pilot. Details Broadcast Technology CP-2013 Composite Audio Processor Excellent baseband processor like Modsci CP-803. Details Orban 222A Only for the purists a Bob's way. Classic Stereo Spatial Enhancer No increase in FM multipath. Details Aev ThunderFrom Italy Composite Audio Processor Excellent stereo separation Regeneration of 19 Khz pilot. Details Aev Luxor 3D From Italy    Stereo enhancer, Digital  delay on audio material. Details BBE 882i & 482i Sonic Maximizer AdaptiveHigh Definition Dynamic HF Enhancer. Details