Boots – shoes – and leggings
Patent
1992-08-25
1994-09-06
Nguyen, Long T.
Boots, shoes, and leggings
341143, G06F 1531
Patent
active
053454065
ABSTRACT:
Improved integration and simplified construction of direct conversion receivers is achieved by providing selectivity in the early stages of a sigma delta converter to reject adjacent channel signals and thereby allow greater dynamic range for the desired input signals. A bandpass sigma delta converter is taught which is suitable for use with signals having multiple protocols. In a first stage, an aliased input signal is applied to two filters having desired and preferably programmable filter characteristics which provide selectivity to the input signal. A third filter is utilized having a programmable center frequency, which receives as an input signal the sum of the filtered input signal plus the quantization noise of the first stage. This provides a first intermediate output signal of desired selectivity. Quantization noise of the first stage is also applied to a second filter stage which provides a second intermediate output signal having a first component related to the quantization noise of the first stage, and a second component which is the shaped quantization noise of the second stage. The first and second intermediate output signals are combined in order to provide a desired output signal in which the original input signal has been filtered to provide a desired selectivity and converted to a digital signal while the quantization noise of the first stage has been cancelled, and the quantization noise of the second stage has been shaped by a desired function and converted to a digital signal independent of the input signal shaping.
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Caserza Steven F.
Nguyen Long T.
Wireless Access Inc.
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