





TANDBERG Codec C90 and Profiles using C90
| ContentsContents |
| IntroductionIntroduction |
| AdvancedAdvancedconfigurationconfiguration |
| PassPasswordord protectionprotection |
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AboutAboutmonitorsonitors
AudioAuAudio mattersattersers
Administrator guide
| AppendicesAppendices |
| ContactContactusus |
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The equalizer
The system has 8 user defined equalizers, each made up of 6 second order IIR sections, see the illustration below. Each of these 8 equalizers can be applied to one or more of the audio input and output connectors on the codec.
The Audio Console application
We recommend using the Audio Console, with the build in equalizer GUI, to modify the equalizers. The Audio Console application is found at the TANDBERG Developer Zone web page.
Go to: http://developer.tandberg.com/web/guest/tools/
The equalizer filter parameters
Each section (1 … 6) of each user defined equalizer (1 … 8) can be modified independently by setting the four parameters:
• Filter type (Peaking, low shelf, high shelf, low pass, high pass) |
The filter types
The illustrations below shows the 5 different filter types and frequency response variations dependent on some of the parameter variations. The
dB | Peaking filter |
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| dB | Low pass and high pass filters |
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101 | 102 | 103 | 104 | 102 | 103 | 104 | |
| Frequency (Hz) |
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| Frequency (Hz) |
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dB | Low shelf filter |
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• | Frequency |
• | Gain |
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To switch off one of the six equalizer sections; set the second order section to have a flat frequency response. This can be done by setting the filter type to “none” or by setting the filter type to “peaking” and the gain to “0” (zero).
8
6Gain = 6 dB
4Gain = 4 dB
2Gain = 2 dB
0
Gain =
Gain =
Gain =
101 | 102 | 103 | 104 |
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6 | Gain = 6 dB |
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4 | Gain = 4 dB |
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2 | Gain = 2 dB |
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Frequency (Hz) | Frequency (Hz) |
The equalizer IIR filter |
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Section 1 |
| Section 2 |
| Section 3 |
| Section 4 |
| Section 5 |
| Section 6 |
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b1 | b1 | b1 | b1 | b1 | b1 | ||||||
a1 | a1 | a1 | a1 | a1 | a1 | ||||||
b2 | b2 | b2 | b2 | b2 | b2 | ||||||
a2 | a2 | a2 | a2 | a2 | a2 | ||||||
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| www.tandberg.com |