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©2020
Rev 1.1
17
Hardware Registers
Register 0x03 SYNTH_MODE (1 Byte)
This register configures the PLL loop gain of the local oscillator synthesizers. It also enables or disables
faster tuning of the YIG based oscillator of LO1.
Bit Type Name
Width Description
[0]
WO
Lock Mode
1
0 = harmonic offset mode
1 = fracN PLL offset mode
[1]
WO
Loop Gain
1
0 = Normal loop gain for better close in phase
noise.
1 = Low loop gain for better far out phase noise
and spur suppression.
[2]
WO
Disable spur
suppression
1
Only applies in harmonic offset mode, see bit [0].
0 = The device automatically switches to fracN
offset mode to avoid potentially large spurs due
to intermodulation between the carrier and the
harmonics of the reference clock.
1 = This disables the function and may speed up
tuning speed in some cases.
[7:3]
WO
Unused
5
Set all bits to zero.