After careful consideration, Hitachi Kokusai Electric Comark LLC will end technical and

Transcription

1 MODAP Setting Up ADAPT-IV Exact DTV Exciter Exciter Corrector Support Introduction After careful consideration, Hitachi Kokusai Electric Comark LLC will end technical The repair Comark support Exact for exciter MODAP has a very ADAPT-IV capable series / powerful of Digital non-linear TV Exciters digital pre-corrector on April 28, contained Only in module it. Knowing level how parts to will set be up available properly for a adjust limited this time corrector beyond April is key 28, to best performance safe operation of a transmitter. Described below is a basic guide to There allow are a user several to accomplish conditions that proper led to this adjustment decision, of including: this corrector. Connecting 1. Components Feedback used Signals in both MODAP ADAPT-IV Exciters are no longer On rear available panel re from are vendors. 2 SMA The connectors original design labelled of FBA MODAP (Feed Back Exciter Amplifier), is over 20 FBF (Feed years Back old Filter). design of ADAPT-IV Exciter is over 12 years old. They are first second generation DTV Exciters deployed by Hitachi-Comark. The FBA signal should come from transmitter output sample before mask filter. This is 2. used The for MODAP non-linear (shoulder) ADAPT-IV correction. Exciters have not been supported by original The FBF stock signal of should exciter come components from for transmitter repairs. output sample after mask filter. This is used for linear (SNR) correction. 3. Hitachi-Comark can supply our EXACT Exciter to replace eir MODAP or These signal ADAPT-IV levels should Exciters. be EXACT in range is Hitachi-Comark s of -15 to -5 dbm. fourth generation DTV Exciter. is priced competitively. MODAP Exciter Versions of ADAPT-IV Exciters Reasonable efforts will be made to maintain parts until end of support. However, prior to that time, some parts or assemblies may no longer be available for eir purchase or repairs. Technical support parts support will no longer be provided after April 28, This technical assistance. REV B 13 March,

2 Checking Feedback MODAP Signals ADAPT-IV Levels DTV Exciter Support Once feedback signals are connected, user can check, in Exact Precorrections Menu, that y are properly wired, synchronized, that ir power levels are in accordance After careful with consideration, specifications. Hitachi Kokusai Electric Comark LLC will end technical repair support for MODAP ADAPT-IV series of Digital TV Exciters on April 28, Only module level parts will be available for a limited time beyond April 28, There are several conditions that led to this decision, including: 1. Components used in both MODAP ADAPT-IV Exciters are no longer available from vendors. The original design of MODAP Exciter is over 20 years old design of ADAPT-IV Exciter is over 12 years old. They are first second generation DTV Exciters deployed by Hitachi-Comark. 2. The MODAP ADAPT-IV Exciters have not been supported by original 3. Hitachi-Comark can supply our EXACT Exciter to replace eir MODAP or ADAPT-IV Exciters. EXACT is Hitachi-Comark s fourth generation DTV Exciter. Setting Crest is Factor priced competitively. Protection Clipping Parameters The only parameters that need to be set before launching DAP are Crest Factor, Protection Clipping, Timer (Correction Time). Crest Factor Setting Since Exact is performing a clever PAPR reduction, less destructive for signal compared to amplifier, Crest Factor has to be reduced as much as possible by Exact instead of amplifier. As a tool, Crest Factor value monitored from amplifier feedback signal can be used as a guide / starting point. Once transmitter is at full power before correction is run for first time, crest factor / PAPR can be read in FBA Measurements section of Corrections page. This is Crest Factor / PAPR that MODAP Exact Exciter is measuring on transmitter output without correction. The recommended starting point is to set Crest Factor setting Versions only of ADAPT-IV about 1dB Exciters higher than value which is monitored in FBA Measurements section. This should not be set to what you believe Crest Factor / PAPR should be when you are finished correcting Reasonable efforts will be made to maintain parts until end of support. However, or as referenced by any or measurement means. prior to that time, some parts or assemblies may no longer be available for eir pur- REV B 13 March,

3 Protection Clipping MODAP Setting ADAPT-IV DTV Exciter Support Protection Clipping is just what name implies. It is maximum level of PAPR allowed out of exciter when correction is run. Because DAP corrector simply tries to After make careful feedback consideration, signal Hitachi as close Kokusai to perfect Electric as possible Comark it LLC essentially will end knows technical no limits of repair how support far it can for stretch MODAP peaks unless ADAPT-IV told orwise. series of If Digital this is not TV Exciters kept to a on reasonable April 28, level it Only could module result in level amplifier parts damage. will be available A good for guideline a limited is time to keep beyond this April only about 28, dB above crest factor setting. Once correction has run, it should be adjusted down by There 1dB are from several where conditions is set to that see led if re to this a decision, performance including: impact. If not, n leave it alone. It should only be carefully increased in small increments to see if increasing has any positive 1. Components effect on signal used in performance. both MODAP Essentially, ADAPT-IV it should Exciters be adjusted are no only longer as high as necessary available to achieve from vendors. acceptable The performance. original design of MODAP Exciter is over 20 years old design of ADAPT-IV Exciter is over 12 years old. They are first second generation DTV Exciters deployed by Hitachi-Comark. 2. The MODAP ADAPT-IV Exciters have not been supported by original 3. Hitachi-Comark can supply our EXACT Exciter to replace eir MODAP or ADAPT-IV Exciters. EXACT is Hitachi-Comark s fourth generation DTV Exciter. is priced competitively. Once Crest Factor Protection Clipping have been set, DAP can be launched in Precorrection Menu, using one of following modes: Single mode (recommended), where DAP will be automatically stopped after a user configurable Timer value. Continuous mode, where DAP works continuously until user exit continuous mode MODAP Exciter Versions of ADAPT-IV Exciters Reasonable efforts will be made to maintain parts until end of support. However, prior to that time, some parts or assemblies may no longer be available for eir purchase or repairs. Technical support parts support will no longer be provided after April 28, This REV B 13 March,

4 Timer Setting MODAP ADAPT-IV DTV Exciter Support In Precorrections menu if Single mode is selected amount of time corrector will run can be adjusted. In most cases 3 to 5 Minutes is sufficient for good performance of After careful non-linear consideration, corrector. By Hitachi not setting Kokusai Electric value too Comark low or LLC short, will end shoulder technical performance repair support may for not reach MODAP its best performance ADAPT-IV series level as of Digital corrector TV Exciters has not on run April enough 28, iterations Only of module correction level to parts linearize will be available transmitter for optimally. a limited time By setting beyond it April excessively 28, high or long, transmitter performance will have already reached optimum performance There are before several conditions corrector that has led stopped. this decision, Setting it including: too long can potentially have ill effects in that shoulders could become over corrected not be at optimum performance. 1. Components used in both MODAP ADAPT-IV Exciters are no longer available from vendors. The original design of MODAP Exciter is over 20 years old design of ADAPT-IV Exciter is over 12 years old. They Crest Factor are first Parameter second Setting generation Fine Tuning DTV Exciters deployed by Hitachi-Comark. After a first run of DAP (in single mode with a timer value set), it is usually possible 2. The MODAP ADAPT-IV Exciters have not been supported by original to fine tune Crest Factor setting in order to improve achieved shoulders performance. This change should be made in small increments (0.1 to 0.3dB) eir up or down from original set value while observing shoulder performance. If performance 3. Hitachi-Comark gets better, try going can supply a little our more EXACT in that Exciter direction to replace until eir performance MODAP starts or to degrade ADAPT-IV n back Exciters. up a bit EXACT to best is Hitachi-Comark s performance. Once fourth this generation is done, reset DTV Exciter. correction, It is currently re-run available DAP. for This ATSC should 1.0, yield easily equal upgraded or perhaps for ATSC slightly 3.0 better compatible, performance. The corrector is priced competitively. is now optimally adjusted. Crest Factor Optimization Parameter Setting For a given Crest Factor, Crest Factor Optimization enhances signal shoulders. Finding best value for this parameter allows user to gain performance on shoulders of signal, thus optimizing amplifier power. This shoulder optimization involves a MER / SNR performance reduction. The user must find best trade-off for shoulder performance vs. MER/SNR performance. This parameter can vary in a range from 0 (Off or None) to 255 (Max). When Crest Factor Optimization parameter is increased, shoulder level becomes better. At same MODAP time, Exciter MER performance decreases. As explained earlier, a trade-off between two is necessary to obtain best Versions overall of ADAPT-IV optimization Exciters desired signal performance. There Reasonable is a useable efforts will range be made for to Crest maintain Factor parts Optimization until end parameter of support. between However, about 50 prior to 150. that time, Below some 50 on parts this or setting assemblies not too may much no effect longer is be noticed. available Above for eir 150 on purchase or repairs. MER / SNR performance will likely be too far this setting degraded. Technical support parts support will no longer be provided after April 28, This REV B 13 March,

5 Hitachi Kokusai Electric Comark LLC 104 Feeding Hills Road Southwick, MA U.S.A. (800) REV B 13 March,