Version: 1.18
PRELIMINARY/CONFIDENTIAL
TrueSpeech® Co-Processor
Table 12-3: Electrical Characteristics Over Recommended Operating Free-Air Temperature Range
(Unless Otherwise Noted)
PARAMETER
TEST
CONDITIONS
MIN
TYP
MAX
UNIT
VOH high level output voltage
VOL low level output voltage
IOZ off state output current
VCC = 5V
2.4
V
V
0.6
20
VCC = Max
µA
µA
II input current
±20
(pins without pull down resistors)
II input current
(pins with pull down resistors)
+20
-60
µA
ICC Supply Current
Operating Mode
Stop Device
Mode
f = 45.056 MIPS
VCC = 5V
mA
mA
0.5
50
2
No Clock
VCC = 5V
uA
25 °C
all inputs GND
all outputs NC
CI Input capacitance
20
pF
Table 12-4: DTMF & Tone Generation Characteristics
PARAMETER
DTMF twist (high/low tone)
MIN
TYP
MAX
UNIT
dB
2
±8
+0.1
+6
Tone generator frequency accuracy
Tone generator level*
Tone generator level accuracy
-0.1
-24
-0.5
%fc
dB0
dB
+0.5
* 0 dB0 is 0.707 VRMs programmable with 2 dB resolution. Assumes FSYNC = 8.000 KHz
Table 12-5: Acoustic Echo Canceller Performance
PARAMETER
Acoustic Echo Cancellation
Max echo delay
NOTE
30 dB
10ms
1
2, 3
Notes:
1. The acoustic echo canceller achieves 30 dB of cancellation for white noise in less than 1.0 seconds with the
speaker CODEC output connected to the microphone CODEC input via a 2:1 attenuator and an output
level equivalent to -10 dBm0.
2. The acoustic echo canceller can cancell echos up to 10ms (approximately 3.4 meters or 11 feet in sound
propagation.
3. Assumes operation of CODEC at 8.0 KHz sample rate.
CT8022A11AQC FW Revision 0118 DSP GROUP, INC., 3120 SCOTT BOULEVARD
SANTA CLARA, CA 95054 PH: 408 986 – 4300 FAX: 408 986 – 4490
173
All specifications are subject to change without prior notice.