D51 Datasheet, PDF (1/2 Pages) Frequency Devices, Inc. – Telephone Message & Circuit Noise Measurement

D51 Series
C-Message Response
Description
The D51 is designed specifically to provide the C-
message weighting frequency response specified in
Bell System Technical Reference 41009 for tele-
phone message circuit noise measurement. The
theoretical C-message characteristic simulates the
perceived response of the human ear to telephone
noise.
The D51 filter provides a close, ±1db approximation
to the theoretical C-message weighting function
from 60 Hz to 5.0 kHz.
Telephone Message &
Circuit Noise Measurement
Applications
• Telephone Message Circuit Noise Measurement
• Test Equipment
Theoretical Frequency Response
Frequency
Hz
60
100
200
300
400
500
600
700
800
900
1000
1200
1300
1500
1800
2000
2500
2800
3000
3300
3500
4000
4500
5000
Attenuation
dB
55.7
42.5
25.0
16.5
11.4
7.5
4.7
2.7
1.5
0.6
0.0
0.2
0.5
1.0
1.3
1.3
1.4
1.9
2.5
5.2
7.6
14.5
21.5
28.5
Tolerance
±dB
1
1
1
1
1
1
1
1
1
1
0.1
1
1
1
1
1
1
1
1
1
1
1
1
1
Frequency Response Curve
0
-10
-20
-30
-40
-50
50 100 200
500 1K 2K
5K
FREQUENCY (Hz)
1
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