3DUWLFXODU
3XUSRVH,&
Speech Synthesis IC
s
Fixed phrase play back
Item
Synthesis method
Sampling frequency
Speech data memory
Speech*
(ADPCM)
Synthesizing
time
Melodies & sound
effects
(PCM+waveform
element)
96 Kbit
mask ROM
4 seconds
typ.
30 seconds
typ.
256 Kbit
mask ROM
12 seconds
typ.
85 seconds
typ.
Device
µ
PD7755
µ
PD7756A
µ
PD7757
µ
PD7758A
µ
PD77P56
µ
PD7759
ADPCM, PCM + waveform element
5, 6, 8 kHz
512 Kbit
mask ROM
24 seconds
typ.
170 seconds
typ.
1 Mbit
mask ROM
50 seconds
typ.
340 seconds
typ.
256 Kbit
one time
PROM
12 seconds
typ.
85 seconds
typ.
• 20-pin DIP
(300 mil)
• 24-pin SOP
(450 mil)
1 Mbit
external
50 seconds
typ.
340 seconds
typ.
• 40-pin DIP
• 52-pin QFP
Package
• 18-pin DIP (300 mil)
• 24-pin SOP (375 mil, 450 mil)
*: The synthesis time for the speech is the value for a 6 kHz sampling.
s
Record/play back
µ
PD77501
Speech coding method
Sampling frequency
Compressed speech data rate
External memory type
Applications
Record/play back
time
12kbps
18kbps
24kbps
DRAM area (4M bits
4 max.)
Message record/play back
Approximately 23 minutes and 18 seconds
Approximately 15 minutes and 30 seconds
Approximately 11 minutes and 30 seconds
• DTMF receiver
• Band-pass filter
• Microphone amplifier (fixed/variable gain)
ADPCM
6 kHz
2 bits (12 kbps), 3 bits (18 kbps), 4 bits (24 kbps)
ROM/SRAM area (1M bits max.)
Fixed phrase play back, response message record/play back
Approximately 1 minute and 27 seconds
Approximately 1 minute
Approximately 44 seconds
• 10-bit over sampling A/D, D/A converters
• ADPCM encoder/decoder
• Host CPU interface
4.75 to 5.25 V
35 mA typ. (6 mA max. during power down)
CMOS
• 80-pin QFP (0.65 mm pitch)
Internal functions
Supply voltage
Supply current
Process
Package
µ
PD77502
Speech coding method
Sampling frequency
Compressed speech data rate
External memory type
Applications
Record/play time length
Functions
Supply voltage
Supply current
Process
Package
DRAM area (4M bits
4 or 16M bits
1)
In Coming Message
60 minutes
• FLC Encoder/Decoder
• Echo Canceller (For Full duplex speaker phone application)
• DTMF/Sine Wave/etc, Generator
5 V ±10%
120 mA (operate mode), 20 mA (power down mode)
CMOS
• 100-pin QFP (0.65 mm pitch)
FLC Merhod (Fixed point Low bit rate Coding)
(FLC is a unique NEC method based on CELP)
(CELP = Code Exited Linear Predictive coding)
8 kHz
4 kbps
ROM (or SRAM) area (16M bits max.)
Fixed. OGM *
1
, Users OGM *
1
60 minutes
µ
/A low PCM I/F
• Host CPU I/F
• Silence Compression
*1 : OGM: Out Going Message
96
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