A Digital Signal Processor (DSP) needs:
- Input and Output filtering
- Analogue to Digital to Analogue conversion
- A digital processing unit
DSP's are used for PRECISION, ROBUSTNESS and FLEXIBILITY.
Precision: In theory it is just the precision of DSP systems that is limited by the conversion process at input and output. However in reality it is the sampling rates and word length restrictions that modify this. The increasing operating speed and word length of modern digital logic is allowing many more areas of application.
Robustness: Digital systems are less susceptible to electrical noise pick up and component tolerance variations than analogue systems. Adjustments for electrical drift and component aging are essentially removed which is important complex systems.
Flexibility: It's programmability allows you to upgrade and expand the process operations without incurring large scale hardware changes. You can construct practical systems with time varying and adaptive characteristics.
In the above diagram the sampling frequency defines the number of samples per unit of time taken from a continuous signal to make a discrete signal.
The inverse of the sampling frequency is the sampling interval, which is the time between samples.
QUANTISATION
The majority of modern soundcards support 16bit word length coding, of the quantised sample values.
This represents 65536 different signal levels within the input voltage range on the soundcard.
EG. If the voltage range of an input connection is +/-5V, the range is 10V. A 16bit system therefore has a quatisation step of (10/65536V) = 0.15mV. And this is the smallest voltage difference from this system.
DYNAMIC RANGEThe dynamic range is the ratio of the largest signal amplitude to the smallest.To calculate the dynamic range:
20log([Voltage Range]/{Quantisation step size})dB
=20log(65536)dB
=96dB
In the human ear, we have a dynamic range of >120dB
In the above diagram the sampling frequency defines the number of samples per unit of time taken from a continuous signal to make a discrete signal.
The inverse of the sampling frequency is the sampling interval, which is the time between samples.
QUANTISATION
The majority of modern soundcards support 16bit word length coding, of the quantised sample values.
This represents 65536 different signal levels within the input voltage range on the soundcard.
EG. If the voltage range of an input connection is +/-5V, the range is 10V. A 16bit system therefore has a quatisation step of (10/65536V) = 0.15mV. And this is the smallest voltage difference from this system.
DYNAMIC RANGEThe dynamic range is the ratio of the largest signal amplitude to the smallest.To calculate the dynamic range:
20log([Voltage Range]/{Quantisation step size})dB
=20log(65536)dB
=96dB
In the human ear, we have a dynamic range of >120dB
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