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What are filters in analog circuits?
A filter is a circuit capable of passing (or amplifying) certain frequencies while attenuating other frequencies. Thus, a filter can extract important frequencies from signals that also contain undesirable or irrelevant frequencies. In the field of electronics, there are many practical applications for filters.
What are different techniques of analog communication?
Modulation techniques are roughly divided into four types: Analog modulation, Digital modulation, Pulse modulation , and Spread spectrum method. Analog modulation is typically used for AM, FM radio, and short-wave broadcasting.
What are the methods of filter design?
Digital Filtering The filter design methods provided in the DFD toolkits include Kaiser window, Dolph-Chebyshev window, and equi-ripple for FIR filters; and Butterworth, Chebyshev, Inverse Chebyshev, and Elliptic for IIR filters.
What are the different types of analog filters?
Physical analog filters are typically created using operational amplifiers or transistor-based gain elements with resistors and capacitors. Many different implementation topologies are possible. Efficient analog topologies that lend themselves to physiological filtering requirements include the Sallen and Key implementations.
How are transfer functions implemented in analog filters?
Analog filters are developed to implement transfer functions defined by a ratio of polynomials. These same polynomial ratios can be implemented using digital filtering methods by employing an intermediate transform, such as the Bilinear Z-transformation.
When does aliasing occur in a digital filter?
Aliasing is the generation of spurious signals when the data fed to the digital filter has frequency components that are greater than the filter sample rate (Fs) divided by 2. This phenomenon is known as under-sampling. It’s important that no frequencies in excess of Fs/2 are permitted to be sampled by the ADC.
Why do you need to pre filter analog data?
Pre-filtering the analog data is required to match the analog data bandwidth to the Nyquist requirements established by the ADC sampling rate. The analog signal amplification and pre-filtering processes optimize the A/D conversion for best performance.