Table of Contents
Advertisement
·12.
Circuit Description
2.1 Gonfiguration and Outline
The cabinet of the JRL-2000F consists of a front panel, a top cover, a bottarn cover, a
rear panel and a main chassis.
The equipment of the cabinet consists of the following five units:
Unit Name
Installation Position
Power amplifier
At the bottom of the main chassis on the righted side
Power supply unit
At the bottom of the main chassis on the left-hand side
Matehing circuit
Upper part of the main chassis
Antenna switch
Upper part of the rear panel
Control
Upper part of the main chassis
Switch panel
Display
Frontpanel
The operation of each unit will be described below. Refer to the External View (page
30) for the general configuration and Print Circuit Board Layout (page 55) for the parts
Iayout of the unit, respectively.
_ ,
2.2 NAH-232 Power Amplifier Unit
This unit is attached to the lower part of the main chassis on the righthand side. lt
amplifies the drive input power sent from the exciter up to the rated output power by
the wide-band linear power amplifiers.
This unit consists of two CAH-377 power amplifiers attached to each heat sink respec-
tively, a CCB-367 PA control circuit attached to the upper side of the heat sink, a CFF-
361 power combiner circuit attached to the bottarn side of the heat sink, and a cooling
fan.
2.2.1 CAH-377 Power Amplifier
CAH-377 power amplifier consists of two identical
wide-b~md
linear amplifers which
operate independently of each other on the printed circuit board. Each wide-band
amplifier has 12 RF power MOSFETs and amplifies a 20 W PEP input power to 250W
PEP.
The RF power MOSFET is new generation's power device which has excellent resis-
tance tothermal stress and reflected power, a high linearity and a low high-arder
intermodulation distortion(IMD), as compared with the conventional bipolar transistor.
As the two wide-band linear amplifiers have the same circuit, the circuit operation will
be described for the left part of the connection diagram on page 39.
The inputpower signal from J1 is sent to the input transformer T1, and divided into
two signals with 180° phase difference.
4
I
Downloaded by
RadioManuai.EU
Hide quick links:
Advertisement
Chapters
Table of Contents
