Analyzing And Testing Low Pass Filters For Anti Aliasing

862 Words Oct 27th, 2015 4 Pages
Digital Audio Technology
Filter Testing and ADC Filter Report

Analysing and Testing Low-Pass Filters for Anti-Aliasing
1.1 AIMS
The aim of this lab is to test the response and characteristics of an undefined filter circuit. This report will present the data collected in the lab sessions, interpret this data and discuss the filter’s suitability for use in an anti-aliasing circuit in an analogue-to-digital converter (ADC).
1.2 ANALOGUE-TO-DIGITAL CONVERSION AND ALIASING ADCs are used to convert analogue signals to digital signals so that they can be processed by digital systems such as a computer. This is particularly relevant to audio recording because signals from recording equipment, such as microphones and electronic instruments, are in an analogue format, and must be converted to a digital format in order to be processed by a digital audio workstation (DAW) on a computer. Analogue electrical signals are “continuous”, meaning that data can take an infinite number of values between the maximum and minimum voltages. There are also an infinite number of steps on the time scale and so data at any moment in time can take any value within the scale. Sound travels through air via changes in air pressure and can be represented by sound pressure level (SPL); this is a continuous scale and so the pressure can be any value at any given moment in time. When sound is processed by a transducer, such as a microphone, these changes in SPL are replicated by changing the…
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