FEBL7731-02-02
1
Semiconductor
User’s Manual for
MSM7731-02 Evaluation Board
- 14 -
5.
HOW TO CONTROL THE EVALUATION BOARD FOR BEST QUALITY VOICE
5.1
Overview
The voice quality is a key factor for a hands-free kit. The high-performance echo canceler, noise canceler
and codec of the MSM7731-02 can realize the best quality voice.
In order to get the best quality voice, it is required to control the peripheral circuits for the MSM7731-02.
This chapter describes how to get the best quality voice using the MSM7731-02 evaluation board. The
following control method for the MSM7731-02 is described when the EC mode is the single EC mode and
the line interface is the analog interface.
STEP 1: Initial settings of switches on the evaluation board
STEP 2: Level control of the path from MIN to SP (speaker)
STEP 3: Level control of the path from SP (speaker) to MIN
STEP 4: Level tuning of the path from MIN to SP with a cellular phone connected.
STEP 5: Level tuning of the path from MIC (microphone) to MOUT with a cellular phone connected,
and control of voice quality
5.2
Instruments
•
Audio analyzer (ex. HP-made 8903B)
•
Sound level meter (ex. RION-made NL-05)
•
Oscilloscope
•
Two sets of cellular phones
5.2
Control Procedure
5.3.1 STEP 1
The STEP 1 performs initial settings of DIP switches (DSW1 to DSW6) and variable
resistors (RV1, RV2, RV4, RV5) on the evaluation board.
(a)
Set all the switches of DSW1 to “0”.
(b)
Set each switch of DSW2 as follows:
1 - CLKSEL:
Set this switch to “0” to select the internal clock mode.
2 - ECSEL:
Set this switch to “1” to select the single echo canceler mode.
3 - MCUSEL:
Set this switch to “1” to select the pin control mode.
4 - PCMSEL:
Set this switch to “0” to select the 16-bit linear.
7 - GLPADTHR:
Set this switch to “0” to disable GLPAD.
8 - LINEEN:
Set this switch to “0” to enable the line CODEC.
RV1
RV2
TPAD
RV5
RPAD
RV4
Evaluation Board
N
ear-end
C
e
llular Phone
Far-end
C
e
llular Phone
MIN
MOUT
MIC
SP
STEP 2
STEP 4
STEP 3
STEP 5