Nautel NV30LT-N, Руководство по эксплуатации и техническому обслуживанию

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NV30LT-N OPERATIONS & MAINTENANCE MANUAL DESCRIPTION
PAGE 3.1.4 VERSION 0.1 2015-03-01
RF Drive Stage
See electrical schematics Figure SD-6 (single exciter) or SD-7 (dual exciters). The RF drive stage converts
the exciter's RF output to the intermediate RF level needed to drive the RF power modules. It consists of
exciter A (A4), optional exciter B (A5), a coaxial relay (K1), a 3 dB hybrid splitter (A32), 30 kW RF drive
splitter assembly (A27), and 10 kW RF drive splitter assemblies (A7, A19, A35 and A43).
Exciter(s)
Exciter A (part of controller module A4) and B (A5, optional) are the RF drive sources for the transmitter.
They accept the external audio program information (see the NV30LT-N Pre-installation Manual for
details on various program input types). For dual exciter applications, the exciters’ main/standby
operation is controlled locally using the front panel UI, or remotely using the web-based AUI. The
exciter outputs are applied to the RF drive splitter/changeover assembly (A27). The exciter provides a
nominal RF drive signal of 520 W (in analog mode).
RF Drive Splitting/Changeover
See also electrical schematics Figure SD-35 and SD-39. Coaxial relay K1 controls the routing of the main
exciter and, if applicable, the standby exciter and provides the RF drive signal for the 30 kW RF drive
splitter assembly (A27), which is the first stage of RF drive splitting. A secondthird stage of RF drive
splitting is provided by 10 kW RF drive splitter assemblies (A7, A19 and A35), which split the outputs of
the 30 kW RF drive splitter into 12 RF drive signals for the 12 RF power modules.
Coaxial Relay Control - Dual Exciters Only
The RF drive outputs from exciters A and B are applied to the coaxial relay at K1-N/C and K1-N/O,
respectively. The Exciter Relay Control input (K1-E1) is a signal applied from the control/monitor stage,
via the reject load/splitter interface assembly (A28) that controls relay K1. The control/monitor stage
provides a +15 V dc power supply on K1-E2.
 When exciter A is selected as the main RF drive source, the Exciter Relay Control input is open
circuit. Coaxial relay K1 de-energizes and applies exciter A’s RF drive signal to the 20 kW RF
drive splitter.
 When exciter B is selected as the main RF drive source, the Exciter Relay Control input is near
ground potential (0 V). Coaxial relay K1 energizes and applies exciter A’s RF drive signal to the
20 kW RF drive splitter.