PSB4860HV4.1 Lantiq, PSB4860HV4.1 Datasheet - Page 41

• Manufacturer Part Number: PSB4860HV4.1
• Manufacturer: Lantiq

Specifications of PSB4860HV4.1

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Note: In addition, attenuation is also influenced by the Automatic Gain Control stages
Note: By programming parameter DS to 0xFF idle mode is disabled and the
2.1.3.4
The PSB 4860 can report the current state of the echo suppression unit to ease
optimization of the parameter set of the echo suppression unit. In this case the SPS
SPS
Table 7
Furthermore the controller can read the current value of the SPS pins by reading register
SPSCTL.
2.1.3.5
The speakerphone unit can also be used for controlled loudhearing. This is enabled by
setting bit MD in register SCTL. If loudhearing mode is enabled, the loudspeaker
amplifier of the PSB 4851 (ALS) is used instead of GHR (figure 16) when appropriate to
avoid oscillation. To use this feature, the PSB 4851 must be programmed to allow ALS
override. The ALS field within the AFE control register AFECTL defines the value sent to
the PSB 4851 if attenuation is necessary (see specification of the PSB 4851).
2.1.3.6
The echo suppression unit has two identical automatic gain control units AGCX and
AGCR both referred to as AGC in this section.
Whether the automatic gain control AGC amplifies or attenuates depends on whether the
signal level is above or below the threshold level defined by parameter COM. The
threshold is relative to the maximum PCM-value and thus negative. The parameters
AG_GAIN and AG_ATT determine the maximal amplification and attenuation,
respectively. The bold line in Figure 21 gives an example for the steady-state output level
of the AGC as a function of the input level.
Data Sheet
SPS
0
0
1
1
1
pins are set according to table 7.
(AGCX, AGCR) in order to keep the total loop attenuation constant.
speakerphone will remain in the last state. This parameter must be set before
enabling the speakerphone.
0
Echo Suppression Status Output
SPS Output Encoding
Loudhearing
Amplifiers with Automatic Gain Control
SPS
0
1
0
1
1
Echo Suppression Unit State
no echo suppression operation
receive
transmit
idle
41
PSB 4860
2000-01-14
0
and