User's Manual

CDMA and GSM / UMTS Mini Card Hardware Integration Guide
30 Proprietary and Confidential 2130114
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.
Thetypicalhandsetsidetoneis12dBbelowtransmit voice
levels.
ForHandsetandHeadsetmode,thethresholdofpain
(+120dBSPL)mustnotbeexceededatthemaximumvolume
setting.Agoodtargetforthemediumvolumesettingis
+94dBSPL,asthisisatypicallevelforconversationalspeech.
Most
audiogainshouldbeaddedtothehostaudiofront end
(withinthePDAstylecodecgainblocksoramplifiersbetween
thehostcodecand transducers).Refertothe appropriateMini
CardProductSpecificationDocumentforreferencelevelson
themodemreceiveandtransmitside.
Echo cancellation support
TheMiniCardoffersfourmodesofechocancellationto
supportuniqueend‐unitaudiocapabilities(echocancellation
canalsobeturnedoffcompletely).Allechocancellationis
near‐end(mobileTX)cancellationonly.Thenetworkprovides
someleveloffar‐endechocancellation.
Table 4-3: Echo cancellation details
Mode Details
Handset
• Short echo path (<16 ms travel time from speaker to
microphone)
• Handset design requires good isolation between
speaker and microphone
• Echo canceller allows full-duplex conversation with
absolute minimum echo
Headset
• Short echo path (<16 ms travel time from speaker to
microphone)
• Headset design may allow higher echo than
handset mode—microphone and speaker are physi-
cally closer
• More aggressive echo canceller algorithm allows
full-duplex conversation on headsets with good
isolation
Car kit
• Long echo path (<64 ms travel time from speaker to
microphone)
• Loud echo
• For use with hands-free car kit or speakerphone
applications with mild distortion