
AN93
Rev. 1.4
225
7.6.4.3. Speakerphone Transition
A SP Button On Event will trigger the transition to Speakerphone system voice mode. Based upon the point at
which the event is received, the voice driver will vector to a user answer state to gracefully exit the TAM PSTN
mode.
7.6.4.4. Handset Transition
A Handset Raised Event will trigger the transition to Handset system voice mode. Based upon the point at which
the event is received, the voice driver will vector to a user answer state to gracefully exit the TAM PSTN mode.
7.7. Speakerphone
7.7.1. Overview
The Si2494/39 speakerphone consists of the following function components as shown in Figure 31 on page 200:
Acoustical echo canceller (AEC)
Acoustical echo suppressor (AES)
AEC double-talk detector (DTD)
Line echo canceller (LEC)
Howling controller (HC)
High-pass filter (HPF)
7.7.2. External Microphone/Speaker Calibration
The Si2494/39 speakerphone calibration is required for a new external speaker and microphone pair to work
properly with the speakerphone code. This section covers the following procedures:
To calibrate the speaker and microphone module from a commercial reference platform to have the same
speaker loudness and microphone sensitivity relative to those of the active reference system.
To calibrate the speakerphone gains so that the AEC/DTD input signal levels are ensured for optimal AEC/AES/
DTD performance.
The external analog gains on the Si24xx-VMB should be finalized before the performing the speakerphone
calibration.
7.7.2.1. Transmit Gain Calibration—Speakerphone Disabled
Figure 34 illustrates the reference setup where the commercial speakerphone is active with default settings. Using
the reference commercial speakerphone, call the remote telephone and establish a voice call. Place a sound
source such as a PC speaker at a distance of one foot from the speakerphone’s microphone. Play out white noise
as the near-end speech through the sound source, and adjust the white noise level so that the level at the
speakerphone’s Tip/Ring is -15 dBm. Record the white noise level and disconnect the call.
AT+VTS=[500,0,100]
OK
Play special administrator tone.
[Playback Menu Options]
Using the +VTX command, the voice driver
can playback a menu and monitor DTMF
digit events to perform operations
remotely.
Table 146. TAM PSTN Interrupted Answer – OGM Playback with DTMF Menu Entry (Continued)
Host to Modem Commands / Data
Modem to Host Result
Codes/Data
Local Modem Actions
Содержание Si2404
Страница 2: ...AN93 2 Rev 1 4 ...
Страница 27: ...AN93 Rev 1 4 27 Figure 7 Parallel Interface Read Timing Figure 8 Parallel Interface Write Timing ...
Страница 200: ...AN93 200 Rev 1 4 Figure 31 TAM Handset and Speakerphone Voice Paths ...
Страница 201: ...AN93 Rev 1 4 201 Figure 32 Si3000 Codec Gain and Signal Selection Options ...
Страница 290: ...AN93 290 Rev 1 4 Figure 57 256 Band Spectral Display Figure 58 2048 Band Spectral Display ...
Страница 305: ...AN93 Rev 1 4 305 Figure 76 Parallel or SPI Port Interrupt Service Flowchart ...