User Guide

NPE-4
3 - Audio System PAMS Technical Documentation
Page 3-16 ãNokia Corporation. Original
UEM microphone input specification:
Buzzer
Alerting tones and/or melodies are generated by a buzzer, which is controlled by a PWM
signal from the UEM. The SPL requirement is to be as good or better than the NPE-3 in
comparison test. The buzzer is delivered from the supplier with an end of line require-
ment of 102dB (A) at 5cm and 2.5 kHz.
The actual level is found from a comparison with NPE-3 on specific ringing tones.
The buzzer is designed to have the first resonant peak at 2500 Hz. The ringer melodies
will be optimised in DSP so the main frequency of any given melody is shifted to near the
resonant peak. For this optimisation a program called BuzzCalc will be used for the cal-
culation of the dominating frequency of a given ringing melody or tone.
The design of the buzzer is a direct copy from the NPE-3 project. The Buzzer is glued to a
gasket. This final assembly is delivered by STAR. Sound holes are placed in the A-cover
The A-cover is designed to give an optimal SPL by securing the tightness between buzzer
and A-cover.
The buzzer is electrically connected to the PWB by spring contacts.
Table 6: Microphone input specifications
Parameter Symbol Min Typ Max Unit
Microphone amplifier input resistor R
M30
30 50 kOhm
Differential input voltage range for MIC1
input, G =20 dB
V
IN1
200 1200 m V
PP
Receive Common mode input voltage
range for MIC input
V
HFCM
100 m V
PP
Common mode voltage level V
CM
1.3 1.35 1.4 V
Differential mode voltage range for
microphone amplifier, at gain = 20dB
V
OUT
2.0 V
PP
Differential load resistance for the
microphone input stage
R
OS
30 450 kOhm
Transmit gain absolute accuracy GXA -1.0 0.0 dB
Transmit gain variation with programmed
gain, temperature and supply
GXAGT
V
-0.7 0.7 dB
Common mode rejection ratio CMRR 45 60 dB