Anritsu 682XXB - Manual (Page 33)

used to fine tune and phase lock the YIG-tuned
oscillator. The A11 PCB also contains circuitry
for frequency modulation of the YIG-tuned os-
cillator RF output.
The CPU sends control data to the A3 Reference
Loop PCB, the A4 Coarse Loop PCB, and the A5
Fine Loop PCB via the A16 PCB as serial data
words. The CPU controls the A11 FM PCB via the
dedicated data and address bus. Refer to paragraph
2-3 for a functional overview of the frequency syn-
thesis subsystem.
Analog
Instruction The A12 Analog Instruction PCB provides the fre-
quency tuning voltages and frequency band select
signals to the A13 YIG Driver PCB. For models with
a frequency range greater than 20 GHz, it supplies
frequency band select signals to the A14 SDM, SQM
Driver PCB. In addition, it provides a 0V to +10V
ramp signal to the rear panel
HORIZ OUT connector,
a V/GHz signal to the rear panel V/GHz OUT connec-
tor, and a SLOPE signal to the A10 ALC PCB for
slope-vs-frequency correction of the RF output
power. The CPU controls the A12 Analog Instruc-
tion PCB via the dedicated data and address bus.
YIG Driver The A13 YIG Driver PCB supplies the main tuning
current and bias voltages for the 2 to 20 GHz YIG-
tuned oscillator. It also provides bias voltages for
the Down Converter assembly and the amplifiers lo-
cated in the Switched Filter assembly.
The A12 Analog Instruction PCB provides (1) fre-
quency tuning voltages for the main tuning coil
driver of the YIG-tuned oscillator and (2) frequency
band select signals to activate the appropriate bias
voltage supply.
Function
Generator The A8 Function Generator PCB provides internally
generated waveforms for amplitude and frequency
modulation. The waveforms available are sine wave,
square wave, triangle wave, positive ramp, negative
ramp, Gaussian noise, and uniform noise. The AM
waveforms are supplied to the A10 ALC PCB and
the rear panel
AM OUT connector; the FM wave-
forms are provided to the A11 FM PCB and the rear
panel
FM OUT connector. The CPU controls the A8
Function Generator PCB via the dedicated data and
address bus.
682XXB/683XXB MM 2-5
FUNCTIONAL 682XXB/683XXB
DESCRIPTION MAJOR SUBSYSTEMS
NOTE
When Option 6 (phase modulation)
is installed, the A8 Function Gen-
erator uses its internal FM genera-
tor to provide the available wave-
forms for both frequency and phase
modulation.