Anti-aliasing filter
AssigneeMediatek Inc.
InventorsTien-Yu Lo, Chan-Hsiang Weng, Patrick Cooney, Tsung-Kai Kao, Stacy Ho
Life of this patent
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Abstract
The invention provides an anti-aliasing filter (AAF) for discretization at a sampling period. The AAF may include an operational amplifier having an input terminal and an output terminal, a first capacitor coupled between the input terminal and the output terminal, a second capacitor, and a first switch coupled between the first capacitor and the second capacitor. During a first phase, the first switch may conduct the second capacitor to the first capacitor. During a second phase, the first switch may stop conducting the second capacitor to the first capacitor. The first phase may last for one said sampling period.
Claims24
An anti-aliasing filter (AAF) for discretization at a sampling period, comprising:
- an operational amplifier having an input terminal and an output terminal;
- a first capacitor coupled between the input terminal and the output terminal;
- a second capacitor;
- and
- a first switch coupled between the first capacitor and the second capacitor;
- wherein:
- during a first phase, the first switch conducts the second capacitor to the first capacitor;
- during a second phase, the first switch stops conducting the second capacitor to the first capacitor;
- and
- the first phase lasts for one said sampling period, such that a signal transfer function of the AAF has one or more notches at one or more integer multiplications of a sampling frequency, with the sampling frequency being a reciprocal of said sampling period.
An AAF for discretization at a sampling period, comprising:
- a first filter comprising an operational amplifier which has an input terminal and an output terminal;
- a second filter comprising a capacitor;
- and
- a switch circuit coupled between the first filter and the second filter;
- wherein:
- during a first phase, the switch circuit conducts the second filter to the input terminal and the output terminal;
- during a second phase, the switch circuit insulates the second filter from the input terminal and the output terminal;
- and
- the first filter further comprises a first resistor coupled between a front node and the input terminal.
An anti-aliasing filter (AAF) for discretization at a sampling period, comprising:
- an operational amplifier having an input terminal and an output terminal;
- a first capacitor coupled between the input terminal and the output terminal;
- a second capacitor;
- and
- a first switch coupled between the first capacitor and the second capacitor;
- wherein:
- during a first phase, the first switch conducts the second capacitor to the first capacitor;
- during a second phase, the first switch stops conducting the second capacitor to the first capacitor;
- and
- the first phase lasts for one said sampling period, so as to achieve anti-aliasing when an output signal of the AAF is sampled at said sampling period.
An anti-aliasing filter (AAF) for discretization at a sampling period, comprising:
- an operational amplifier having an input terminal and an output terminal;
- a first capacitor coupled between the input terminal and the output terminal;
- a second capacitor;
- and
- a first switch coupled between the first capacitor and the second capacitor;
- wherein:
- during a first phase, the first switch conducts the second capacitor to the first capacitor;
- during a second phase, the first switch stops conducting the second capacitor to the first capacitor;
- and
- the AAF further comprises a first resistor coupled between a front node and the input terminal;
- and
- the first phase lasts for one said sampling period, so as to achieve anti-aliasing when an output signal of the AAF is sampled at said sampling period.
Dependencies are inferred from the claim text.