Table of Contents
Advertisement
5-6. TAD (SF3000T Only)
TAD circuit consists of a voice coprocessor to record and play voice messages in voice memory.
5-6-1. Recording path
R62 provides power to the condenser microphone.
Voice signal from the microphone is passed through
active filter U22, R60 and C51, R58, C48 to clear
aliasing noise occuring while sampling and
amplifying the signal. Q5 and Q4 compose ALC
(Automatic Level Control) circuit. CODEC (U29)
converts the voice signal to digital and converts the
digital signal from voice coprocessor into analog for
line output.
5-6-2. Mic input path
Transmit path functions as MIC input path.
Outgoing messages and memo messages from
CODEC are stored in the voice memory (4Mb
DRAM) through the DSPG DRAM controller.
Samsung Electronics
5-6-3. Line input and play path
Incoming signals from line are stored in the voice
memory (4Mb DRAM) through CODEC and DSPG
DRAM controller. When played, DSPG processes
the data stored in voice memory and sends it out to
LIU through CODEC and R93. To playback through
the speaker, DSPG sends the signal to speaker
through R93, MUX (U25, U26), and op amp.
5-6-4. DSPG
This circuit consists of Host Interface, Memory
Interface, CODEC Interface, and DSP core. Host
Interface sends and receives data to and from IFC.
Memory Interface sends and receives the
compressed voice data to and from DRAM to play
back and record voice data. DSP core communicates
with host IFC through Host Interface.
5-6-5. Voice backup
+5V is supplied for voice memory through VBT
when power is on. When power is off, +5V is
supplied from the 9V backup battery.
Circuit Description
5-15
Advertisement
Table of Contents
