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5.11. Microphone
The microphone is a noise canceling type to provide improved speech pick-up, noise immunity and reduced echo. The
GSM Standard requires that when in handheld mode, the transmitter audio frequency response must fit within the mask
shown below:
5.12. Receiver
5.12..1. Handheld Mode
Because IOTA is powered from a 2.85 V supply, a low impedance (dynamic) speaker must be used. The GSM Standard
requires that the receiver audio frequency response must fit within the mask shown below:
The phone is designed to meet requirements with a Type 1 artificial ear.
Volume Levels
Volume Level
PGA
Volume
Total Gain
1
5 dB
-12 dB
+6.21 dB
2 2
dB
-12
dB
+5.12
dB
3 -1
dB
-12
dB
+1.82dB
4 -2
dB
-18
dB
-6.43
dB
5 -2
dB
-24
dB
-12.76
dB