BM28723AMUV
14 Digital Sound Processing (DSP) - continued
14.4 Bi-quad Type Filter
This LSI has the following blocks that have a feature of the Bi-quad type filter:
12 Band BQ, Crossover filter of 3Band DRC block and BQ of the soft transition.
The shapes that can be used are peaking filter, low shelf filter, high shelf filter, low pass filter, high pass filter, all path filter
and notch filter.
Setting the coefficient of the digital filter (b0, b1, b2, a1, a2) in the LSI by transmitting to the coefficient RAM via command.
12 Band BQ have the soft transition function. Note that the detailed order of the parameter setting refers to the following
BQ setting method.
Select of BQ independent or dependent setting
Default=0x0
Select Address
0x60[4]
Value
0x0
Explanation of Operation
L/R dependent setting
0x1
L/R independent setting
0x60[4] setting note.
Reset all the Bi-quad type filters when you change the setting of 0x60[4].
The Bi-quad type filters for which the re-setting is necessary are 18 BQs of BQ1-12, DRC1,DRC2 and DRC3 (Each DRC
has 2 band).
Select the destination of BQ soft transition
Default=0x00
Select Address
Explanation of Operation
0x51[4:0]
Destination
12BAND(1)
12BAND(2)
12BAND(3)
12BAND(4)
12BAND(5)
12BAND(6)
12BAND(7)
12BAND(8)
12BAND(9)
12BAND(10)
Destination
12BAND(11)
12BAND(12)
Value
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
Value
0x0A
0x0B
Select of soft transition
Default=0x0
Select Address
0x53[6]
Value
0x0
Explanation of Operation
Use soft transition
0x1
Not use soft transition
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