UBS Axcera 420A Low Power Television User Manual

UBS-Axcera Low Power Television Table of contents

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Chapter 2

100 Watt High Band VHF Transmitter Chapter 2, System Description420A, Rev. 0 2-1Chapter 2System DescriptionThe 420A is a complete 100 watt highband VHF solid-state internally diplexedtelevision transmitter that operates at anominal visual output power of 100 wattspeak sync and an average aural outputpower of 10 watts at a 10 dB A/Vratio,10% sound.The 420A has been submitted for typeacceptance to the FCC; the relevant FCCidentifier for the 420A is_________________.2.1 420A System OverviewThe 420A (1066428) consists of (A1) a100-watt, high-band VHFexciter/amplifier tray (1066308) and (A2)a bandpass filter assembly.The exciter/modulator section of the 100-watt, high-band VHF exciter/amplifiertray operates using either basebandaudio and video inputs. However, if the(optional) 4.5 MHz composite input kit(1273-1128) is purchased, the 4.5 MHzcomposite input or the baseband videoand audio inputs are used to produce adiplexed, modulated, on-channelfrequency visual + aural RF output. Theswitching between the 4.5 MHzgenerated by the baseband inputs or bythe 4.5 MHz composite input isaccomplished by a relay, on the sync tipclamp modulator board. The relay iscontrolled by a baseband select whichconnects to J18-6 and 7 on the rear ofthe tray. To operate the transmitter withthe (optional) 4.5 MHz composite inputkit using baseband inputs, the basebandvideo must be connected to J1 or J2, thebaseband audio must be connected tothe proper input jack, and a basebandselect must be connected to J18-6 and 7.To operate the transmitter with the(optional) 4.5 MHz composite input kitusing the 4.5 MHz composite input, the4.5 MHz composite input must beconnected to J1 or J2 and the basebandselect must be removed from J18-6 and7.The exciter/modulator section of the traytakes the baseband audio and videoinputs, or the (optional) 4.5 MHzcomposite input, and produces acombined 45.75 MHz + 41.25 MHz IFoutput that connects to J32 on the ALCboard. The combined IF output of theALC board connects to themixer/amplifier assembly where it isupconverted and filtered to the on-channel frequency visual + aural RFoutput. The RF is filtered and amplified inthe amplifier section to the 100-wattoutput power level. The RF output isfiltered in the bandpass filter assemblyand fed to the antenna via thetransmission line.The exciter and upconverter section ofthe tray operate when the circuit breakerCB1 is on, but the amplifier section onlyoperates when the transmitter is inOperate. This occurs because theswitching power supply that supplies theoperating voltages to the amplifiersection has an inhibit command appliedto it, shutting it off as long as thetransmitter is in Standby.2.1.1 Exciter SectionThe baseband video and audio inputs tothe transmitter connect to the rear panelof the tray. The baseband video or the(optional) 4.5 MHz composite inputconnects to jack (J2), which is a loop-through connected to jack (J1). Byremoving the termination jumper on thesync tip clamp/modulator board, jack(J1) can be used as a connection for thebaseband video or the 4.5 MHzcomposite input to another transmitter.The baseband audio input connects tothe terminal block (TB1) for balanced
Download:
Mirror Download [FCC.gov]
Document ID80249
Application ID4c+HKm7jMl4rg9yoqQg3Tw==
Document DescriptionChapter 2
Short Term ConfidentialNo
Permanent ConfidentialNo
SupercedeNo
Document TypeUser Manual
Display FormatMicrosoft Word - pdf
Filesize4.75kB (59393 bits)
Date Submitted2000-01-10 00:00:00
Date Available2000-04-03 00:00:00
Creation Date2001-05-03 07:56:05
Producing SoftwareAcrobat Distiller 4.0 for Windows
Document Lastmod2001-05-03 07:56:07
Document TitleChapter 2
FCC ID Filing: OUS420A

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