msm7617 Oki Semiconductor, msm7617 Datasheet - Page 23

• Manufacturer Part Number: msm7617
• Description: 2-channel Echo Canceler
• Manufacturer: Oki Semiconductor

¡ Semiconductor
ECHO CANCELER CHARACTERISTICS DIAGRAM
Characteristics of m-law and A-law are identical. (Characteristic graphs below are reference
data.)
Note: regarding dBm0:
The "dBm0" unit used in the characteristic graphs is a unit that expresses PCM CODEC digital
values. Therefore, be aware that the same value 0 [dBm0] might correspond to different analog
input levels depending on the PCM CODEC being used. Please check the data sheet of the PCM
CODEC being used.
Example
Measuring Conditions:
RIN input level = –10 dBm0 white noise
Echo delay time = 50 ms
ATT, GC, NLP, LR all off
40
30
20
10
40
30
20
10
0
0
0
40
MSM7533
MSM7543
Echo Delay Time vs. Echo Attenuation
ERL vs. Echo Attenuation
10
30
E. R. L. [dB]
Echo Delay Time [ms]
20
20
10
30
–10 [dBm0] = 0.27 [Vrms] = 0.76 [Vp-p] = –9.2 [dBm] 600 W
–10 [dBm0] = 0.19 [Vrms] = 0.54 [Vp-p] = –12.2 [dBm] 600 W
0
0 [dBm0] = 0.85 [Vrms] = 2.4 [Vp-p] = 0.8 [dBm] 600 W
0 [dBm0] = 0.6007 [Vrms] = 1.7 [Vp-p] = –2.2 [dBm] 600 W
40
–10
50
60
Measuring Conditions:
RIN input = white noise
Echo delay time = 50 ms
E.R.L. = 6 [dB]
ATT, GC, NLP, LR all off
40
30
20
10
0
RIN Input Level vs. Echo Attenuation
Measuring Conditions:
RIN input level = –10 dBm0 white noise
Echo delay time = 50 ms
E.R.L = 6 dB
ATT, GC, NLP, LR all off
–50 –40 –30 –20 –10
RIN Input level [dBm0]
0
MSM7617
10
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