CS47L85 datasheet(210/370 Pages) CIRRUS

210 / 370 page

CS47L85

210

Rev 4.3

OUTPUT SIGNAL PATH DIGITAL FILTER CONTROL

An integrated signal processing engine on the CS47L85 supports digital filter requirements for range of Hi-Fi applications.

Preset filter coefficients are held in on-board ROM, and can be configured and enabled as required. The Hi-Fi filters are

tailored to specific sample rates, and provide options relating to passband frequency, stopband attenuation, and phase

response characteristics.

The filter type is selected using the HIFI_FIR_TYPE register field. The available filters are each described in Table 74. The

digital filter can be enabled in any output path, using the respective OUTnx_HIFI control bits.

Note that only one filter type can be selected at any time, but the applicable filter can be enabled on any number of output

paths simultaneously. The supported sample rates for each filter type are noted in Table 74; the selected filter must be

consistent with the output sample rate (OUT_RATE) setting.

The digital filter can be enabled or disabled independently in any output path. A short interruption to the playback if the filter

type is changed whilst the Hi-Fi filters are enabled on any output path.

The Hi-Fi digital filters are described in Table 74.

TYPE

SAMPLE

RATE

DESCRIPTION

PASSBAND

STOPBAND

PASSBAND

RIPPLE

STOPBAND

ATTENUATION

48 kHz,

44.1 kHz

Deep stopband, Linear Phase

0.454 fs

0.546 fs

0.001 dB

120 dB

Deep stopband, Minimum Phase

0.454 fs

0.546 fs

0.001 dB

120 dB

Anti-alias, Linear Phase

0.417 fs

0.5 fs

0.001 dB

110 dB

Anti-alias, Minimum Phase

0.417 fs

0.5 fs

0.001 dB

110 dB

96 kHz,

88.2 kHz

Non-apodizing, Linear Phase

0.227 fs

0.5 fs

0.001 dB

120 dB

Non-apodizing, Minimum Phase

0.227 fs

0.5 fs

0.001 dB

120 dB

Apodising, Linear Phase

0.227 fs

0.454 fs

0.001 dB

120 dB

Apodising, Minimum Phase

0.227 fs

0.454 fs

0.001 dB

120 dB

192 kHz,

176.4 kHz

Non-apodizing, Linear Phase

0.114 fs

0.5 fs

0.001 dB

125 dB

Non-apodizing, Minimum Phase

0.114 fs

0.5 fs

0.001 dB

125 dB

Apodising, Linear Phase

0.114 fs

0.454 fs

0.001 dB

125 dB

Apodising, Minimum Phase

0.114 fs

0.454 fs

0.001 dB

125 dB

Table 74 Output Signal Path Digital Filter Types

At 48kHz (or 44.1kHz) sample rate, the key parameters of the Hi-Fi digital filters are the stopband attenuation and phase

response. The stopband characteristics are noted in Table 74.

The choice between linear phase and minimum phase filters determines time-domain effects of the filter transfer function.

Linear phase offers zero group delay, and equal levels of pre- and post-ringing. Minimum phase offers minimum pre-ringing

and latency, but higher levels of post-ringing and group delay distortion.

For sample rates above 48kHz, a choice between apodizing and non-apodizing filters is available. Apodizing filters have the

capability to reduce time-domain distortion

– this can be used to eliminate ‘time smear’ effects introduced by other filters in

the signal chain, provided the other filters have a flat frequency response throughout the apodizing filter’s cut-off region. The

cut-off (stopband) frequency of the apodizing filters are slightly lower than the respective non-apodizing filter response.

CS47L85 Datasheet(PDF) 210 Page - Cirrus Logic

CS47L85 Datasheet(HTML) 210 Page - Cirrus Logic

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL