![Panasonic EB-X300 Service Manual Download Page 32](http://html.mh-extra.com/html/panasonic/eb-x300/eb-x300_service-manual_261901032.webp)
– 5-11 –
Figure 5.10. U201 Functional Block Diagram
The microphone is a noise cancelling 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:
Figure 5.11. Handheld GSM Transmit Audio Frequency Response Mask
5.3.2. Microphone
5
0
-5
-10
-15
1,000
10,000
100
Frequency (Hz)
(dB)
In base-band power management, ADI U201 is designed for all base-band main power supply.
It provides seven regulator outputs for VCORE (1.8V), VMEM (2.93V), VEXT (2.93V), VRTC (1.8V), VCTCXO (2.75V),
VSIM (2.85V), VMIC (2.75V). VCORE and VMEM provide all digital power and VMEM provides all analogue power.
VRTC is used to charge Li-Mn coin cell for real time clock, and VCTCXO is the power source of 13MHz clock buffer.
U101 also provides the charge pump and hardware reset.
Mic
Filter
Filter
Filter
Filter
Tone
Battery
Charger
Light
Controllers
8 Voltage Regulators
Crystal &
Varactor
LEDs
Headphones or Headset
VCORE: 1.8 V, 80 mA
VRTC: 1.8 V, 200
µ
A
VMEM: 1.8 V or 2.8 V, 150 mA
VSIM: 1.8 V or 2.85 V, 20 mA
VEXT: 2.8 V, 170 mA
VABB
VMIC: 2.5 V, 1 mA
VVCXO: 2.75 V, 10 mA
CSPORT
BSPORT
ASPORT
Switch
GMSK
Ram
DAC
DAC
DAC
DAC
DAC
ADC
ADC
ADC
ADC