Programming Information
67
Bit 3 = 1
Bit 2 = 1
4.
Determine the value of f
h
as shown in
Section 3.5.21
Register 39h (73h), Input
High Pass Filter Tuning on page 61
and then select the step value:
f
h
= 6000 Hz
Selecting the step value from
Table 3.5.28 on page 62
: step = 11b
5.
Writing the bits to register 3Bh
Register 3Bh = 00001111b = 0Fh
3.5.24 Register 3Eh (7Dh), Demodulator Offset Nulling Loop
This register, in conjunction with the Loop Stress Status register 33h, forms a
demodulator tracking loop.
Figure 3.5.24
illustrates the breakout of register bit
assignments.
Figure 3.5.24: Register 3Eh Bit Assignments
Table 3.5.32: Demodulator Offset Null Register Definition
Loop stress data is read from status register 33h and the loop is centered with
register 3Eh. When the 4430-V is first tuned to a new carrier frequency, status
register 33h should be read and register 3Eh should be used to center the loop.
Due to the wide tuning range, the offset nulling loop should always be used to
null out the changing mixer offset.
7
6
5
4
3
2
1
0
0/1
0/1 0/1
0/1
0/1
0/1
0/1
0/1
Offset Null [Bit weight = 1] LSB
Offset Null [Bit weight = 2]
Offset Null [Bit weight = 4]
Offset Null [Bit weight = 8]
Offset Null [Bit weight = 16]
Offset Null [Bit weight = 32]
Offset Null [Bit weight = 64]
Offset Null [Bit weight = 128] MSB
Bit No.
Bit Name(s)
Functional Description
07-00
Demod Offset Null
See definitions to follow
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
