Audio Filters Circuits
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The filter should provide adjustable gain to maximize SNR at the audio processor's first stage. The filter's frequency response should also include a notch at 19 kHz to achieve maximum attenuation at the FM-subcarrier pilot-tone frequency and thus minimize....
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The three-amplifier implementation of the state-variable filter in Figure 1 provides for second-order bandpass, highpass, and lowpass responses. The strength of the circuit, however, is in the bandpass response (VOUT/VIN), in which it`s easy to achieve high....
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Using a modified equal-element design for a lumped-circuit lowpass filter has several advantages over the well-known equal-element design (Reference 1 and Reference 2). The modified design exhibits superior passband performance with only modest degradation....
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This equaliser is designed as a preamp suitable for musical instruments - guitar, bass and keyboard in particular. Unlike most conventional graphic equalisers, each slider ranges from fully off to fully on, and not the more conventional +/-12dB or so that is....
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Switched-capacitor filters that are preset for a given bandwidth sometimes do not deliver the bandwidth or Q an application requires. By inverting the clock between two switched-capacitor bandpass filters, such as the MSFS1 from Mixed Signal Integration....
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This circuit is taken from the Progressive Communications Receiver in most of the recent ARRL Handbooks. Values for the 40 meter band are shown. If you want the ultimate in a bandpass filter for 40 or 20 meters, check out the bandpass filters in "An....
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There are applications where a particular band, or spread, or frequencies need to be filtered from a wider range of mixed signals. Filter circuits can be designed to accomplish this task by combining the properties of low-pass and high-pass into a single....
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Notch filters remove a single unwanted frequency from an input signal. They are also a vital component of pulse-shaping networks, such as time-averaging filters. You can tune a state-variable filter over a wide range by changing the time constants of its....
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The circuit is completely conventional, and has been around almost forever in one guise or another. Similar circuits were used in the valve (tube) era, so there is nothing new about it. The circuit has already been published on these pages as a guitar....
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With graphic equalizer we make selective cutting off or boost, of selected departments of acoustic spectrum. With this way we can adapt the musical reproduction, in the characteristics of space where we hear. This can create however also problems if go to....
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Although you can obtain universal, resistor-programmable switched -capacitor filters that are configurable as notch filters, most cannot operate at bandwidths higher than 100 kHz. Further, the typically 16- to 20-pin packages do not include a continuous....
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White noise (the sound you hear when a TV is tuned to a non-existent station) has a frequency characteristic which raises the power level by 3dB with each increasing octave, and is not suitable for response testing (and will probably blow your tweeters as....
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The technique applies to highpass filters. You derive a composite highpass filter by using m-derived terminating half-sections with one or more constant-k interior full sections. Classic image-parameter design used m-derived half-sections with m=0.6 for best....
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This project is also an essential part of the expandable analyser to be published soon (or perhaps "eventually"), and one meter circuit is used for each frequency band. There are many other uses for a simple LED VU meter. They are ideal as power meters on....
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Figure 1 illustrates the simplified block diagram of a typical high-speed data converter system. The system consists of a bandpass filter, ADC, high-frequency clock, high-speed storage device, and post processing unit. Aside from the MAX104, the....
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These filters are useful for equalisation, analysis and other tasks such as the Sound to Light converter (Project 62) or even a fully functional Vocoder. For those who have not heard of the vocoder, it is a device that takes a music source as one input and....
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Built around an LM380, this amplifier includes tone controls and electronic "soft switching". The soft switching circuitry ensures power is built up gradually eliminating the dc thump. The soft switching is enabled by a BD131 transistor wired as a switch in....
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The purpose is supposedly to account for the fact that human hearing is less sensitive at low and high frequencies than in the upper midrange, and that this variation is dependent upon the sound intensity (SPL). The Fletcher-Munson curve (as it is commonly....
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The acoustic filters are met in various points in the sound systems. The knownest application they are the filters baxandal for regulating tone low and high frequencies and filters crossover where the acoustic region is separated in subareas, in order to it....
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The electronics consist of three op-amp circuits; each built around one half of an NE5532 dual op-amp. Each circuit uses that op-amp in a different configuration. The first circuit is a non-inverting pre-amp, the second is a unity-gain phase-inverter, and....
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The human speech apprehend a small area of frequencies, that is extended from 300HZ until 3KHZ. This spectrum is also internationally recognized for the transmission of speech via telecommunications networks. This is also the mainer use of this circuit, one....
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The particular circuit does?t have the requirement to replace the trade decoders Surround, because this they have many more facilities and possibilities. It give however the possibility in many try with this article of decoding. The coding in Stereo Dolby....
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It many times happens, we want erase or decrease in a musical song, the voice of singer or some other sound that usually is written in same level and in the two channels. If we remove between them two signals of channels, we can take in the output a mono....
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A simple circuit, High-Pass filter, variable between frequencies 20HZ until 200HZ, useful in a lot of cases elaboration of sound signals. The regulation is achieved with the double potesometer 47K? and the frequency response in his two extreme places,....
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This preamplifier was designed to cope with CD players, tuners, tape recorders etc., providing a gain of 4, in order to drive less sensitive power amplifiers. As modern Hi-Fi home equipment is frequently fitted with small loudspeaker cabinets, the bass....
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The application that to you we propose is a simple filter of region that limits the acoustic region (20-20000Hz) in the region 20-100Hz. With the manufacture that to you we propose you can make a active filter in order to you lead a loudspeaker of very low....
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Two low voltage, low power zeners are used to control electronically the level of an audio signal. The attenuation range is from 6 to 58dB for an input current from 0.042 to 77 mA corresponding to a control voltage from 2.7 to 7.5V. If control voltage is....
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The circuit includes Better channel separation, resulting in an increased stereo effect, as well as reduced noise and hum. This schematic will allow you to cancel or blend left and rigth channels of your stereo. Uses the LM4136 but at the circuit is a 741....
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Two low voltage, low power zeners are used to control electronically the level of an audio signal. The attenuation range is from 6 to 58dB for an input current from 0.042 to 77mA corresponding to a control voltage from 2.7 to 7.5V. If control voltage is....
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If you want to build one yourself, you have to get two audio transformers which have 1:1 transformation ratio and greater than 1 kohm impedance. There are high quality audio transformers in the markes that meet those specs, but those can be quite expensive.....
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The circuit shown is completely conventional. The Q of the filters has been optimised to allow a higher input impedance than would otherwise be possible, with the final Q of the two filters being almost exactly 0.707 (i.e. a traditional Butterworth filter).....
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In the form it appears the theoretical circuit of filter. In first glance we see three different circuits that are mainly manufactured round two operational amplifiers. This circuits constitute mixed, amplifier with variable aid and a variable filter. The....