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Part number: 2
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Haos Redro
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Last update: 14/06/2009
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Fourth order highpass filter module
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Resources:
| 1 |
Overall schematic |
FIG | PDF |
| 2 |
PCB layout |
FIG | PDF (copper) | PDF (copper+component) |
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Description:
An active fourth order highpass filter using a dual operational amplifier. The filter is a Linkwitz-Riley type using two cascaded second order Sallen-Key filters each with a Q factor of 0.707 to give an overall Q of 0.5. The filter was designed for audio applications though it is limited by the capabilities of the amplifier used at frequencies up to the low MHz range. The TL072 can be substituted with a different model should a particular application require it.
Table 1: Component function
| R1-R2-C1-C2-IC1A |
These components form the first Sallen-Key filter. |
| R3-R4-C3-C4-IC1B |
Second Sallen-Key filter. |
| C5,C6 |
Supply rail decoupling capacitors. |
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PCB layout:
The PCB is intended to be integrated into a larger design using right-angled pins so that it stands vertically from the motherboard much like an SIL packaged part. IC1 is centrally located with one half of the filter to each side. All three connectors are located along the lower edge of board.
Power:
The datasheet of the model of op-amp chosen for IC1 should be consulted for information regarding the power requirements of this module.
Images:
Completed module |
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Copyright © 2008 Taiyo Rawle. This document is released under the terms of the TAPR Open Hardware License version 1.0 or at your option any later version, http://www.tapr.org/ohl.html
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