NSW-6
System Module SE2
PAMS Technical Documentation
Page 35
Issue 1 12/99
Nokia Mobile Phones Ltd.
Alert Signal Generation
A buzzer is used for giving alerting tones and/or melodies as a signal of
an incoming call. Also keypress and user function response beeps are
generated with the buzzer. The buzzer is controlled with a BuzzerPWM
output signal from the MAD1. A dynamic type of buzzer is used since the
supply voltage available can not produce the required sound pressure for
a piezo type buzzer. The low impedance buzzer is connected to the
UI–switch ASIC. The alert volume can be adjusted either by changing the
pulse width causing the level to change or by changing the frequency to
utilize the resonance frequency range of the buzzer.
A vibra alerting device is used for giving a silent signal to the user of an
incoming call. The device is controlled with a Vibra output signal from the
MAD1.