ucb1400 NXP Semiconductors, ucb1400 Datasheet - Page 22

• Manufacturer Part Number: ucb1400
• Description: Audio Codec With Touch Screen Controller And Power Management Monitor
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 09611
Product data
9.1.4 Overload detection
9.2.1 DSP features
9.2.2 Noise shaper
9.2 Interpolation filter (DAC)
Two bits in the Feature Control/Status Register 1 (0x6A) provide control over DC
filtering:
An overload detection circuit will inform the user whenever the input voltage exceeds
the maximum input voltage, which will lead to a high distortion. In that case, the OVFL
bit in the Feature Control/Status Register 1 (0x6A) is set. In addition, an interrupt is
generated on the IRQOUT pin of the UCB1400 whenever the OVLP bit or the OVLN
bit is set in the Positive and/or Negative INT Enable Registers.
The digital interpolation filter interpolates from 1 fs to 128 fs by means of a cascade
of FIR filters. The filter characteristics are shown in
Table 7:
The UCB1400 supports the following DSP (Digital Sound Processing) features
through the Feature Control/Status register 1 (0x6A):
In addition, the UCB1400 supports volume control and soft muting via the Master
Volume register (0x02):
The 3rd-order noise shaper operates at 128 fs. It shifts in-band quantization noise to
frequencies well above the audio band. This noise shaping technique enables high
signal-to-noise ratios to be achieved. The noise shaper output is converted into an
analog signal using a Filter Stream Digital-to-Analog Converter (FSDAC).
Item
Pass-band ripple
Stop band
Dynamic range
•
•
•
•
•
•
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DC bit: controls the DC filter before the decimator used to compensate the DC
offset is added in the ADC to remove idle tones from the audio band.
HIPS bit: controls the DC filter at the output of the decimation filter.
Tone control: Bass Boost (BB[3:0]) and Treble Boost (TR[1:0])
Flat/Minimum/Maximum setting for bass and treble boost (M[1:0])
De-emphasis control (DE bit)
Master volume control: The output level can be attenuated in 1.5 dB steps down to
Register (0x02).
Mute: The output is muted when the MM bit in the Master Volume Register is set.
Muting the DAC will result in a cosine roll-off soft mute, using 128 samples in the
normal mode: this results in 3 ms at fs = 44.1 kHz.
94.5 dB independently for the left and right channels via the Master Volume
Interpolation filter characteristics
Rev. 02 — 21 June 2002
Condition
0 to 0.45 fs
> 0.55 fs
0 to 0.45 fs
Audio codec with touch screen controller
and power management monitor
Table
© Koninklijke Philips Electronics N.V. 2002. All rights reserved.
Value (dB)
> 135
7.
0.025
65
UCB1400
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