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Helical Resonator Notch Filter - (electronic circuit
added 7/03) |
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High Q Notch Filter - National Semiconductor Application
Notes first published28-Jun-1996 (app note added 4/02)
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High-Q 60-Hertz Notch Filter - This high-Q notch filter
is based on the "Twin-T" design. It produces a very deep notch in
the response curve at about 59.7 Hz. This is useful to
remove 60-Hz hum and noise from audio recordings or live
performances. Response is down over -60db at the center point. The
LM3900 Norton opamp was chosen since it doesn't require extra....
(Circuit design added 7/06) |
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LB-5: High Q Notch Filter - National Semiconductor
Application Note (app note added 2/06) |
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Notch filter autotunes for audio applications 24-Jun-10 Issue
of EDN Tracking notch filters find use in
harmonic-distortion analyzers; they also can remove heterodyne
noise from ham-radio systems. A conventional tracking
switched-capacitor notch filter relies on a bandpass filter, a
voltage-to-frequency converter, and a notch filter to track the
incoming signal and remove undesired tones. The bandpass filter in
these circuits sometimes adjusts to the wrong frequency, meaning
that the undesired tone would have no attenuation.... [Design Idea
by John R Ambrose, Mixed Signal Integration, San Jose, CA] |
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Notch Filter is DC Accurate - 03/02/95 EDN-Design Ideas....Most active
filters exhibit noise, distortion, gain error, and dc offset. However, a filter
topology that separates the dc and ac paths can eliminate the last two of these
unwanted behaviors (Fig 1a). The dc path in this circuit has no op amps and,
therefore, no dc offset. The dc path does not have a dc gain error other than -6 dB of
attenuation that the R1/R2 divider causes. (This attenuation is absent if you omit the
R2 termination.) The ac path consists of C1 and a synthetic inductor comprising two
wideband transconductance amplifiers and associated components. The result is an
active circuit that emulates the passive filter of Fig 1b....[Design Idea by Gary
Sellani, Maxim Integrated Products, Sunnyvale, CA] |
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Notch Filter is Insensitive to Component Tolerances - 03/02/00 EDN-Design
Ideas Many approaches for creating notch filters, which reject a narrow band of
frequencies and pass all others, are unsatisfactory because they allow the component
tolerances to interact. The circuit in Figure 1a overcomes this limitation and enables
easy calculation of the component values for a desired notch frequency....[Design Idea
added 2/06] EDN migrating links. This link is not verified.
Search the "title" + "EDN" for new link. |
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Notch Filter uses Only Lowpass Filters - 04/10/97 EDN-Design Ideas
[Design Idea added 6/06] EDN migrating links. This link is not verified. Search
the "title" + "EDN" for new link. |
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Notebook Power Supply has Two Outputs - 03/03/94 EDN-Design Ideas The
notebook-computer supply in Fig 1 powers the 5V logic and derives an adjustable -24V
supply for an LCD's backplane. The design uses only a high-efficiency buck regulator
(Si9150]and an NMOS/PMOS, dual-power-FET chip set (Si9943].... [Design Idea by Steven
C Hageman, Calex Manufacturing Co Inc, Concord, CA] |
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Parametric & Graphic Eq's Plus Peaks & Notches - (circuit / schematic design
added 6/06) |
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RC Notch Filter Twin T - The twin T notch filter can be used block an
unwanted frequency or if placed around an op-amp as a bandpass filter. The notch
frequency occurs where the capacitive reactance equals the resistance Xc=R and if the
values are close, the attenuation can be very high and the notch frequency virtually
eliminated. (added 4/02) |
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Reverse RIAA Adaptor - If you’re short of inputs on your amplifier, but it
has an input for a magnetic pickup with RIAA correction, this very simple project will
let you convert this into a high-level linear input, making it compatible with the
outputs from all current audio sources.….must register on this site... [Published in
Elecktor July/August 2010] |
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Reverse RIAA Equaliser - Test phono preamps for correct equalisation, or
convert unused phono inputs. (circuit added 6/07) |
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Simple Easy Parametric & Graphic Eq's Plus Peaks & Notches - (circuit /
schematic design added 6/06) |
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Switched capacitor IC forms notch filter - 09/30/99 EDN-Design Ideas
You can use a switched-capacitor lowpass filter (LPF]to implement an inexpensive notch
filter (Figure 1a]. The internal architecture of the IC (Figure 1b]includes summing
nodes similar to those nodes that analog-signal-processing stages use for
feedback-error generation. The IC lowpass-filters the quantity VIN2VCOM and adds VOS
at the output. In other words,....[Design Idea added 10/06] EDN migrating
links. This link is not verified. Google the "title" EDN for new link.
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Variable notch filter with both high & low pass filters - A variable notch
filter with both high and low pass filters [Andy Collison] |
