Power Driver Integrated Full Digital Audio Amplifier
NTP-8230
+
Ch 1
Ch 2
+
BQ2
BQ2
BQ1
BQ1
2x2
Mixer
Delay
Figure 15. 3D Surround Structure
9.3. Configurable Graphic Equalizer
NTP-8230 provides 5 band graphic equalizer and PEQ to 1/2 channel. EQ on/off can be selected by
EQ flag of register Address 0x0F.
The gains for each band can be controlled by writing the gain values (refer Graphic equalizer band
gain table in Appendix C) to register Addresses 0x10~14 respectively.
In PEQ the BQ1 ~ BQ5 can be used as programmable Bi-Quad filters.
0
BQ1
BQ1
BQ2
BQ2
BQ3
BQ3
BQ4
BQ4
BQ5
BQ5
1
1
0
Figure 16. Configurable Graphic Equalizer
9.4. Post Bi-Quad Filter Chain
The post Bi-Quad filter chains of NTP-8230 can be used in various purposes - bass management,
loudness control, parametric EQ, loud-speaker EQ, etc. Independent filter design for 1, 2 channels are
possible and five 2nd order floating point parametric filters are linked serially. Especially for loudness
control, as shown in Figure 17, last 3 filters are different from first 2 filters.
Filter coefficients are 32-bit floating point numbers and can be downloaded thru I2C interface. To
download post Bi-Quad filter coefficients to NTP-8230, select download channel by using CH flag in
register Address 0x7E first. And then write actual coefficient values to 55 BQ ROM Addresses, from
0x14 to 0x3B for Ch1&2 Control (or 40 BQ ROM Addresses, from 0x0A to 0x18 for Ch3 control).
BQ ROM Address 0x14~0x18 designates 1st chain coefficients and means b0, b1, b2, a1, a2 in
sequence. Address 0x19~0x1D designates 2nd chain, and so on. The enable/disable operation of
these Bi-Quads can be made by using BQF flag in register Addresses 0x17~0x1B(include Ch3 control).
(refer register Address table in Appendix A and refer BQ ROM Address table in Appendix B)
Copyright ⓒ NeoFidelity, Inc.
Page 19
Document Number: DS8230 draft ver. 0.1
2011-01-11
ETC [ ETC ]
