CSR8635 View Datasheet(PDF) - CSR plc

Part Name

Description

Manufacturer

CSR8635

The CSR8635 QFN single-chip Bluetooth® audio ROM device targets mid-range stereo speakers and headsets.

CSR plc 

■ PSKEY_SIDE_TONE_ENABLE

■ PSKEY_SIDE_TONE_GAIN

■ PSKEY_SIDE_TONE_AFTER_ADC

■ PSKEY_SIDE_TONE_AFTER_DAC

9.2.18 Integrated Digital IIR Filter

CSR8635 QFN has a programmable digital filter integrated into the ADC channel of the codec. The filter is a 2-stage,

second order IIR and is for functions such as custom wind noise reduction. The filter also has optional DC blocking.

The filter has 10 configuration words:

■ 1 for gain value

■ 8 for coefficient values

fNCTEToFohhoqlolteeduoeraew:■TfgeitclaihixtnoeSieangnrem1p9oiatsop.rnfI1doslcdeIierost:Ricrneho:FofnonieiPgawoflurbfsefirtlciettpneihhedagreen,rBateeebsnnqditnradauaafrbaopderltyrsieisao.qdpalnTliobna1fhilognni2insrdbt-gtbiorhsdeitteihkqbs000112eeIaueI'11010svRbitDrw.....eleceCf10000ensiodl10000et.mbefz10000nfilrrrhpo10000mo.bolcE10000meiwuktm10000q[ia1ntu10000-her0ga10000eeen]t10000xtiasVoc10000012345678sunnMeipdgl9=====:::::::::ppnvb.ooe2iiat10--mGbbaabbardi[nst9000011112.taohti1212121h]nT,.i,socnetmhtwweoeCpgomhsooescet.sdthrorcieneenwtnievcfbeii-teggSihqtaFu[eun1ttrrthauia1ivdeItmt]eiiaoIoifbsnyonnRe,urtFfmrfhomSu,ieranceblwtlcmpeottNhtrsieoeoeNesrmnn.tAtNottbsahaNieg2kenNrendDN2sifNCi7c1N,a0bN2nlvoN0tacNb1rkNi3itian..bgleisseinnathbeled.

9 : a12

DC Block (1 = enable, 0 = disable)

Filter, H(z)

=

Gain

×

(1

(1

+ b01

+ a01

z−1

z−1

+ b02

+ a02

z−2

z−2

)

)

×

(1

(1

+ b11

+ a11

z−1

z−1

+ b12 z−2 )

+ a12 z−2 )

Equation 9.1: IIR Filter Transfer Function, H(z)

Filter with DC Blocking, HDC (z) = H(z) × ( 1 − z−1 )

Equation 9.2: IIR Filter Plus DC Blocking Transfer Function, HDC(z)

Production Information

© Cambridge Silicon Radio Limited 2013

Confidential Information - This Material is Subject to CSR's Non-disclosure Agreement

Page 45 of 105

CS-303725-DSP5

www.csr.com

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