+ 20dB, +10dB | Telit Wireless Solutions GE863-PY, GE863-QUAD

GE863-QUAD

GE863-PY

1vv0300715 Rev. 1 - 19/09/06

7.1 Microphone Paths Characteristic and Requirements

TIP: being the microphone circuitry the more noise sensitive , its design and layout must be done with particular care. Both microphone paths are balanced and the OEM circuitry should be balanced designed to reduce the common mode noise typically generated on the ground plane. However also an unbalanced circuitry can be used for particular OEM application needs

.

TIP: due to the difference in the echo canceller type, the “Mic_MT” audio path is suited for Handset applications, while the “Mic_HF”audio path is suited for hands-free function (car kit). The Earphone applications should be made using the “Mic_HF” audio path but DISABLING the echo canceller by software AT command. If the echo canceller is left active with the Earphone, then some echo might be introduced by the echo cancel algorithm.

“Mic_MT” 1st differential microphone path

•	line coupling	AC
•	line type	balanced
•	coupling capacitor	≥ 100nF
•	differential input resistance	50kΩ
•	differential input voltage	≤ 1,03Vpp (365mVrms)
•	microphone nominal sensitivity	-45 dBVrms/Pa
•	analog gain suggested	+ 20dB
•	echo canceller type	handset
“Mic_HF” 2nd differential microphone path
•	line coupling	AC
•	line type	balanced
•	coupling capacitor	≥ 100nF
•	differential input resistance	50kΩ
•	differential input voltage	≤ 65mVpp (23mVrms)
•	microphone nominal sensitivity	-45 dBVrms/Pa
•	analog gain suggested	+10dB
•	echo canceller type	car kit hands-free

Reproduction forbidden without Telit Communications S.p.A. written authorization - All Right reserved

page 32 of 79

Image 32

Telit Wireless Solutions GE863-PY Microphone Paths Characteristic and Requirements, + 20dB, Echo canceller type Handset

Contents

GE863-QUAD GE863-PY Hardware User Guide Contents 10.1 10.210.3 10.4 13.2 12.113.1 This document is relating to the following products Overview GE863 module connections PIN-OUT Pin Signal Function Internal Type Pull up Pin Signal Function Internal Type Pins Layout Hardware Commands Turning on the GE863-QUAD/PY Turning OFF the GE863-QUAD/PY Turning off of the device can be done in two ways Hardware Unconditional Reboot Hardware shutdown GE863-QUAD GE863-QUAD/PY power requirements are Power Supply1Power Supply Requirements 2General Design Rules Electrical design Guidelines 1.2 + 12V input Source Power Supply Design Guidelines An example of linear regulator with 5V input is Battery Source Power Supply Design Guidelines An example of switching regulator with 12V input is Battery Charge control Circuitry Design Guidelines Thermal Design Guidelines Power Supply PCB layout Guidelines Antenna GSM Antenna Requirements GSM Antenna PCB line Guidelines GSM Antenna installation GuidelinesSerial Ports Absolute Maximum Ratings -Not Functional Parameter Min Max Level Min Max Signals in the Uart connector on the EVK are Number Pad Number17-28-36 Ground 45-48-50-56 Clear to Send Output from the GE863-QUAD/PY that 3RS232 level translation It is available on the following pins2MODEM Serial Port 2 Python Debug An example of level translation circuitry of this kind is 5V Uart level translation GE863-QUAD Audio Section Overview GM863-GPS Microphone Paths Characteristic and Requirements Echo canceller type HandsetEcho canceller type Car kit hands-free + 20dB That means You can set GA= +20dB to use standard resistor values TIP environment consideration General Design Rules Other considerations Microphone Biasing Balanced Microphone Biasing Unbalanced Microphone Biasing GE863-QUAD Sample circuit can be Microphone BufferingBuffered Balanced Mic Gain = RR604605 = RR607606 Buffer gain is given by the formula Buffered Unbalanced Single Ended Microphone Freq . = 2π * R719* C726 2π * R711* C727 Buffer bandwidth at -3dB shall be 4KHz GE863-QUAD Output Lines Speaker Short description Output Lines Characteristics SW volume level step Number of SW volume steps Noise Filtering Handset Earphone Design Hands-Free Earphone Low Power Design An example of internal Ear amplifier could be Car Kit Speakerphone Design Evaluation Kit for Telit Modules EVK2 Short Description 2 EVK2 Audio Lines Characteristics @ 350mW Data Integrity ESD Schematic SIM Supply Layout General Purpose I/O Using a Gpio Pad as InputUsing a Gpio Pad as Output 10.3Using the Alarm Output GPIO6 Using the Buzzer Output GPIO7 DAC and ADC section 11.1DAC ConverterDescription Min Max Units An AT command is available to use the DAC function Command is AT#DAC=enable,valueEnabling DAC Low Pass Filter Example 11.2ADC Converter Using ADC ConverterInput Voltage range AD conversion Bits Resolution Camera 12.1Transchip CameraType Sensitivity Lux Camera Interface Connectors Camera Physical Detail & Connector Camera Socket Connector Camera Board Module Main Block Diagram for supported cameras Schematic Diagrams for supported camera Taking an reading a photo Camera setting shown here are the defaults onesExample usage script for camera 13.1General 13.2Module Finishing & DimensionsMounting the GE863-QUAD / PY on the Application Board Surface finishing Ni/Au for all test pads Lead-free Alloy Recommended foot print for the application PCB pad Design Debug of the GE863 in ProductionStencil Solder paste 13.2.6 GE863-QUAD / PY Solder Reflow Following is the recommended solder reflow profile GE863-QUAD Packing System Section A-A Modules orientation on tray Moisture Sensibility Conformity Assessment Issues Safety Recommandations Document Change Log Revision Date Changes21/02/06 19/09/06