23-02-2013, 10:34 AM
MATCHED FILTERS
MATCHED FILTERS.pptx (Size: 181.26 KB / Downloads: 22)
INTRODUCTION
Determine the filter characteristics (impulse response or transfer function) that maximize the instantaneous power output with respect to the average output noise power, i.e. design to the criterion
the design criterion minimizes the probability of error for received digital signals.
The linear filter that meets the design criterion is a matched filter.
The transfer function is:
equivalent to convolving the unknown signal with a conjugated time-reversed version of the template.
The matched filter is the optimal linear filter for maximizing the (SNR) in the presence of additive stochastic noise.
The integrate and dump filter.
convolution is an operation on two functions f and g, producing a third function that is typically viewed as a modified version of one of the original functions, giving the area overlap between the two functions as a function of the amount that one of the original functions is translated
Correlation Processing
A specially designed antenna transmits a short burst of radio wave energy in a selected direction.
If the propagating wave strikes an object, such as the helicopter in this illustration, a small fraction of the energy is reflected back toward a radio receiver located near the transmitter.
The transmitted pulse is a specific shape that we have selected, such as the triangle shown in this example
Differential pulse code modulation (DPCM)
is a procedure of converting an analogue into a digital signal in which an analogue signal is sampled and then the difference between the actual sample value and its predicted value is quantized and then encoded forming a digital value.
(predicted value is based on previous sample or samples)