_______________________________________________________________________________________________ Section 3 - Diagram Contents: - Cable diagram - APT139NM2 VEGA Component list - Modules description 57
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Component list APT139NM2 - VEGA Part Name Code Description Qty S0007 MTG0077AR0 MTG0076AR0 MTG0078AR0 MTG0072AR0 MTG0073AR0 MTG0084AR0 MTG0075AR0 MTG0079AR0 MTF0088BR0 05352 OPT016 MODULAR STRUCTURE POWER SUPPLY MODULE EXTERNAL REFEREMENT MODULE MULT. AUDIO STEREO MODULATOR - OPT. MULT. VIDEO MODULATOR MODULE MULT. IF PRECORRECTOR MODULE MULT. LOCAL OSCILLATOR MODULE MULT.
MULT. AUDIO MONO MODULATOR MODULE MTG0071AR1 DESCRIPTION The audio signal enters the module through one 600W balanced or 10kW unbalanced XLR connection, which may be placed either on the front or rear panel and softwareselected. It is conditioned by a digital power-meter with a ±8dB 0.5dB-step dynamic and muting. Then there are the emphasis and clipping stages (which can be inserted via software), before the frequency modulation of the audio carrier.
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The module contains the following blocks: 1. Input relay chooses the audio source between the XLR on the front panel of the module and the one on the back of the apparatus and selects the input impedance to 600W or 10kW; both switching are managed by the software. 2. Audio level regulation stage regulates the level of the audio signal by means of a digital potentiometer which can be programmed trough a uWIRE interface (with 0.5dB step between -8dB and +8dB). 3.
CALIBRATION PROCEDURE - Instrument list MEASURE Lock of the carriers and reference Calibration of the audio parameters after the FM modulation INSTRUMENT - Spectrum analyser - Oscilloscope - Tester - Audio generator - FM Audio receiver - Audio parameters analyser Description of the adjustment points COMPONENT DESCRIPTION R6 FM deviation level R36 Unused R37 Audio carrier level (-6dBm) R99 VU-METER deviation C17 Tuning of the local oscillator of the audio carrier L5 Fine tuning of the local
Component layout for adjustment points 64
The calibration procedure of the module requires a complete structure of display board (see MTG0079) and extension module (see MTG0095) in order to perform the software selection which will be referred to later and power the module itself.
Component layout SCH0198AR3 - Bot layer Component layout SCH0198AR3 - Top layer 66
MULT. AUDIO STEREO MODULATOR MODULE (Option) MTG0078AR0 DESCRIPTION This modulator allows the Mono, Stereo and Dual Sound coding of TV audio signal. The boards accept two input audio channels with a nominal amplitude of 2Vpp ±8dB on a selectable impedance of either 600W balanced or 10kW unbalanced. The selection of the input impedance is made by means of a relay, the adjustment of the input level is made by means of a digital power-meter.
- Peak level of the deviation of the secondary audio subcarrier. All of the operating parameters of the board are managed by the built-in micro-processor. Communication to outside are performed trough RS485 bus.
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The module contains the following blocks: 1. Input relays (2) chooses the audio source between the XLR on the front panel of the module and the one on the back of the apparatus and selects the input impedance to 600W or 10kW; both switching are managed by the software. 2. Audio level regulation stages (2) regulates the level of the audio signal by means of a digital potentiometer which can be programmed trough a uWIRE interface (with 0.5dB step between 8dB and +8dB). 3.
CALIBRATION PROCEDURE - Instrument list MEASURE Lock of the carriers and reference Calibration of the audio parameters after the FM modulation INSTRUMENT - Spectrum analyser - Oscilloscope - Tester - Audio generator - FM Audio receiver - Audio spectrum analyser - Description of the adjustment points COMPONENT DESCRIPTION R161 Clipper symmetry, left channel R176 Clipper symmetry, right channel R13 Indication of the main carrier deviation R134 Indication of the secondary carrier deviation LP1,
COMPONENT MF1, MF2 J2, J7 J4 DESCRIPTION Adjustment of the output filter Audio inputs (panel) IF monitor (panel) Component layout for adjustment points The calibration procedure of the module requires a complete structure of display board (see MTG0079) and extension module (see MTG0095) in order to perform the software selection which will be referred to later and power the module itself.
- Menu of the Multistandard Stereo Audio Modulator Module Verifica sezione oscillatore a IF collegare un analizzatore di spettro sulla monitoria del cassetto J5 e controllare la funzionalità delle sezioni in esso presenti: q Configure the module with IF1 and IF2 On and IF1 Level and IF2 Level at ½ of the scale and calibrate C30 and L7 (C102 and L14) to lock the audio carriers to the intermediate frequency of the set standard (to change the standard refer to the standard change procedure) and obtain a loc
Component layout SCH0210AR1 - Bot layer 74
Component layout SCH0210AR1 - Top layer 75
MULT. VIDEO MODULATOR MODULE MTG0072AR0 DESCRIPTION The video signal enters the module trough a 75W BNC connection which can be selected via software on either the front or rear panel of the apparatus, and is conditioned to the standard value of 1Vpp by a digital power-meter with a maximum dynamic of +/-6dB.
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The module contains the following blocks: 1. Input relay chooses the video source between the BNC on the front panel of the module and the one on the back of the apparatus; the switching is managed by the software. 2. Video level regulation stage regulates the level of the video signal by means of a digital potentiometer which can be programmed trough a uWIRE interface. 3.
peak with a modulation depth of 90% at white level. 13. Vestigial SAW filter filters the double side-band to the broadcast carrier in order to obtain a vestigial modulation (the upper side-band is partially broadcast). 14. IF Amplifier performs the amplification after the vestigial filtering and sums the audio subcarrier(s) coming from the audio modulator module (see MTG0071/78). 15. Output low pass filter filters the presence of harmonics of the audio and video carriers. 16.
- Description of the adjustment points COMPONENT DESCRIPTION R71 White clipper level R92 Level of the video signal in base band (0dB on dig. pot.
Component layout for adjustment points 81
The calibration procedure of the module requires a complete structure of display board (see MTG0079) and extension module (see MTG0095) in order to perform the software selection which will be referred to later and power the module itself.
q Calibrate C113 and L5 to lock the video carrier to the intermediate frequency of the set standard (to change the standard refer to the standard change procedure) and obtain a lock voltage between 7V and 8V on J6 checking that Video is on Lock in the display menu. q In case of problems in obtaining the lock, check that on J4, J7 and J9 there are the frequencies listed in the table of the description of the adjustment points.
84 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig.
Component layout SCH0172AR3 - Top Layer Component layout SCH0172AR3 - Bot Layer 85
MULT. IF PRECORRECTOR MODULE MTG0073AR0 DESCRIPTION The non-linearity IF pre-correction is performed by two distinct stages which act on different characteristics of the signal. The first stage works on ICPM and differential phase and gain (DGDP) of the video signal, which are small signal characteristics and thus need a precorrection based on adapted filtering cells.
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The module contains the following blocks: 1. Input amplifier de-couples the input of the module from the internal pre-correction sections. 2. Input/output relay inserts or excludes the pre-corrector from the IF chain with the timing needed to avoid power overshoot due to the internal AGC stages; the switch is handled by the software and signalled by a yellow LED on the frontal panel. 3.
- Description of the adjustment points COMPONENT DESCRIPTION R12 IF level without pre-correction (-6dBm) R123 IF level before the IMD pre-corrector (0dBm) R126 IF level after the IMD pre-corrector (-6dBm) C57, L11 Band-pass filter on the video carrier of the envelopment demodulator C14, L10 Notch filter on the audio carrier of the envelopment demodulator C23, L9 Tuning of the equalisation band-pass filter R7, C4 Merit and gain factor of the equalisation band-pass filter C20, L7 Tuning of th
Component layout for adjustment points 90
The calibration procedure of the module requires a complete structure of display board (see MTG0079) and extension module (see MTG0095) in order to perform the software selection which will be referred to later and power the module itself. Besides a video modulator module (see MTG0072) and an audio modulator module (see MTG0071/78) already calibrated are needed to calibrate, if neededm the envelopment demodulator (only for the first calibration or to change the standard).
q Configure the module with Prec enabled. q Calibrate R123 to an IF level of 0dBm on R178 and calibrate R126 to an IF level of -6dBm on J10 with the tracking on -6dBm. q Check that the passing band of the section is similar as the one in Fig.6 and able to cover the whole IF band from 30MHz to 50MHz. Verification of the module without pre-correction connect a spectrum analyser with tracking between J3 and J10 and check the sections therein: q Configure the module with Prec disabled.
The testing procedure of the linearity pre-corrector is the consequence of a series of subsequent interventions on the pre-corrector cells in order to achieve a good compromise of the video parameters of the amplifier at the working power. A calibration technique for the cells allowing to satisfy these requirements is proposed below; the choice of the good compromise on the video parameters is anyway entrusted to the skill of the tester.
the compensation has to be found, then the figure reproducing the measure in a specular way is to be considered. In the catalogue there are also the positions of the trimmers and the jumpers to obtain all proposed configurations, of course intermediate solutions are possible and the intensity of all solutions may be scaled by means of the level trimmer which is considered to be at the maximum intervention in the catalogue.
- I.C.P.M.
- I.C.P.M.
- I.C.P.M.
- D.P.
- D.P.
- D.P.
Component layout SCH0209AR1 101
