User Guide

RH-10
System Module CCS Technical Documentation
Page 20 Nokia Corporation Confidential Issue 1 09/2002
Vibra
Introduction
Vibra is located on the D-cover and is connected by spring connectors on the PWB. It is
located in the left bottom side of the engine.
Interfaces
Vibra is controlled by pwm signal VIBRA from UEM. This signal allows control of both
frequency and pulse width of signal. Pulse width is used to control current when battery
voltage changes. Frequency control searches for optimum frequency to ensure silent and
efficient vibrating.
Audio Hardware
Earpiece
Introduction
The 13 mm speaker capsule that is used in DCT3 products also is used in RH-10.
The speaker is dynamical—very sensitive, and capable of producing relatively high sound
pressure at low frequencies. The speaker capsule and surrounding mechanics comprise
the earpiece.
Microphone
Introduction
The microphone is an electric microphone with omnidirectional polar pattern. It consists
of an electrically polarized membrane and a metal electrode, which form a capacitor. Air
pressure changes (i.e., sound) move the membrane, which causes voltage changes across
the capacitor. Since the capacitance is typically 2 pF, a FET buffer is needed inside the
microphone capsule for the signal generated by the capacitor. The microphone needs
bias voltage as a result of the FET.
Parameter Requirement Unit
Rated DC Voltage 1.3 V
Rated speed 9500 ±3000 rpm
Rated current 115 ±20 mA
Starting current 150 ±20 mA
Armature resistant 8.6 ohm
Rated DC voltage available 1.2 to 1.7 V
Starting DC voltage min. 1.2 V