AMX TXC16 Plus Specifications download pdf (Page 22)

SG-2000 MANUAL 15

The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA

mixed with the correct frequency developed by the synthesizer and is then amplified at

the operating frequency.

This amplification process involves several steps: a pre-driver, a driver, and a final

amplifier section which utilizes a splitter - combiner circuit

The pre-driver and the driver sections are very straight-forward in design. But the final

LPA (Linear Power Amplifier) deserves special note because it is very conservatively

constructed. This amplifier is made up of four transistors. While most designers will

use only two, SGC elected to use four for reliability and peak power performance.

Controlling the LPA is a circuit called ALC (Automatic Level Control) which adjusts the

operating conditions of the final amplifier to insure its operation is linear over a wide

range of conditions.

A broad band filter network then matches the high power signal to a 50 ohm output

impedance. This is then sent to the SG-230 Smartuner (which we highly recommend) or

a broad band antenna system such as the SG-103.

4.3 Control Circuits

The SG-2000 is a microprocessor controlled radio. Each of the control heads has a

microprocessor and talks to the microprocessor in the radio unit using the RS-422

communications protocol. This means that the control head may be placed as much as

50 meters away from the radio. Although not supported by SGC, many users of the

control heads have reported success at longer distances. As with all SGC specifications,

50 meters is a conservative number.

The microprocessor control codes, which are generated when the front panel push

buttons are pushed, are sent to the microprocessor in the radio unit which return

confirmation to the control head that the instructions have been acted upon. The head

microprocessor controls the display information and functions such as setting of

volume and squelch levels.

Each of the control heads has a unique device address which allows the micro-

processors in the radio unit to send information as well as establish the intercom

address of the control head.

In the event that you wish to address the microprocessors on the radio unit directly,

you may use the RS-232 serial port which is located on the rear panel of the radio.

Any number of serial ports and heads may be used, as long as the total number of

device addresses does not exceed eight. Four control heads and four computers works

as well as one control head and seven computers.

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AMX TXC16 Plus Specifications Page 22