Measuring circuit and a method for determining a characteristic of the impedance of a complex impedance element for facilitating characterization of the impedance thereof
First Claim
1. A measuring circuit for determining a characteristic of the impedance of a complex impedance element for facilitating characterization of the impedance thereof, the measuring circuit being implemented on a single chip and comprising:
- a signal generating circuit for generating an analog stimulus signal of selectable frequency for applying to the complex impedance element; and
a first receiving circuit for receiving an analog response signal from the complex impedance element in response to the stimulus signal, and for producing a first output signal indicative of the characteristic of the impedance of the complex impedance element; and
a signal processing circuit for carrying out a Fast Fourier Transform on the first output signal to produce a third output signal for use in characterization of the impedance of the complex impedance element.
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Accused Products
Abstract
A single chip integrated circuit measuring circuit (1) for determining a characteristic of the impedance of an external complex impedance circuit (2) for facilitating characterization of the impedance of the complex impedance circuit (2) comprises a signal generating circuit (7) for generating a variable frequency stimulus signal for applying to the complex impedance circuit (2). A first receiving circuit (10) receives a response signal from the complex impedance circuit (2) in response to the stimulus signal and conditions the response signal. A first analog-to-digital converter (68) converts the conditioned response signal to a first digital output signal, which is read from the first analog-to-digital converter (68) through a first digital output port (14). The response signal from the complex impedance circuit (2) is a current signal, and a current to voltage converter circuit (64) converts the response signal to a voltage signal. A first RMS to DC level converting circuit (70) converts the AC voltage of the response signal to a DC voltage level, and a fourth multiplexer (67) selectively applies the voltage response signal or the DC voltage level signal to the first analog-to-digital converter (68), depending on whether it is desired that the first digital output signal should be indicative of the phase shift or amplitude change in the response signal relative to the stimulus signal. A second receiving circuit (20) receives the stimulus signal, and similarly converts the stimulus signal to a second digital output signal for facilitating comparison of the response signal with the stimulus signal.
21 Citations
58 Claims
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1. A measuring circuit for determining a characteristic of the impedance of a complex impedance element for facilitating characterization of the impedance thereof, the measuring circuit being implemented on a single chip and comprising:
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a signal generating circuit for generating an analog stimulus signal of selectable frequency for applying to the complex impedance element; and a first receiving circuit for receiving an analog response signal from the complex impedance element in response to the stimulus signal, and for producing a first output signal indicative of the characteristic of the impedance of the complex impedance element; and a signal processing circuit for carrying out a Fast Fourier Transform on the first output signal to produce a third output signal for use in characterization of the impedance of the complex impedance element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 51, 52)
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31. A method for determining a characteristic of the impedance of a complex impedance element for facilitating characterization of the impedance thereof, the method comprising acts of:
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providing a signal generating circuit on a single chip for generating an analog stimulus signal of selectable frequency for applying to the complex impedance element; providing a first receiving circuit on the single chip for receiving an analog response signal from the complex impedance element in response to the stimulus signal and for outputting a first output signal indicative of the characteristic of the impedance of the complex impedance element for use in characterization of the impedance of the complex impedance element; providing a signal processing circuit on the single chip for carrying out a Fast Fourier Transform on the first output signal to produce a third output signal for use in characterization of the impedance of the complex impedance element; operating the signal generating circuit for applying the stimulus signal to the complex impedance element; applying an analog response signal from the complex impedance element, responsive to the stimulus signal, to the first receiving circuit; operating the first receiving circuit for producing the first output signal indicative of the characteristic of the impedance of the complex impedance element; and operating the signal processing circuit for carrying out a Fast Fourier Transform on the first output signal to produce the third output signal. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. An integrated circuit for producing a signal indicative of a characteristic of the impedance of a complex impedance element for facilitating characterization of the impedance thereof, the integrated circuit being implemented on a single chip and comprising:
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an output terminal through which an analog stimulus signal of selectable frequency is outputted for applying to the complex impedance element; a signal generating circuit for generating the analog stimulus signal; a signal conditioning circuit for conditioning the analog stimulus signal generated by the signal generating circuit and for applying the conditioned analog stimulus signal to the output terminal; a receiving circuit for receiving an analog response signal from the complex impedance element in response to the stimulus signal, and for outputting an output signal indicative of the characteristic of the impedance of the complex impedance element; and a signal processing circuit for carrying out a Fast Fourier Transform on the output signal to produce a further output signal for use in characterization of the impedance of the complex impedance element. - View Dependent Claims (41, 42, 43)
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44. An integrated circuit for producing a signal indicative of a characteristic of the impedance of a complex impedance element for facilitating characterization of the impedance thereof, the integrated circuit being implemented on a single chip and comprising:
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an output terminal through which a stimulus signal in analog form of selectable frequency is outputted for applying to the complex impedance element, a direct digital synthesis frequency signal generator for generating the stimulus signal, the direct digital synthesis frequency signal generator comprising; a phase accumulator comprising a counter for incrementing or decrementing its count by a frequency determining digital word to or from a predetermined maximum count value in response to each cycle of a clock signal, a phase-to-amplitude converter for converting count values from the phase accumulator to digital words representative of amplitude values of a sinusoidal waveform, a digital-to-analog converter for selectively converting the digital words produced by the phase accumulator and the phase-to-amplitude converter for selectively producing the stimulus signal in analog form as one of a triangular waveform and a sinusoidal waveform, and for applying the stimulus signal to the output terminal, and a first switch circuit for selectively coupling the phase accumulator and the phase-to-amplitude converter to the digital-to-analog converter to selectively produce the stimulus signal in analog form as the one of the triangular waveform and the sinusoidal waveform, and a receiving circuit for receiving a response signal in analog form from the complex impedance element in response to the stimulus signal, and for outputting an output signal indicative of the characteristic of the impedance of the complex impedance element for use in characterization of the impedance of the complex impedance element. - View Dependent Claims (45, 46, 47, 48, 49, 50)
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53. An integrated circuit for producing a signal indicative of a characteristic of the impedance of a complex impedance element for facilitating characterization of the impedance thereof, the integrated circuit being implemented on a single chip and comprising:
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a signal generating circuit for generating an analog stimulus signal of selectable frequency for applying to the complex impedance element; a receiving circuit for receiving an analog response signal from the complex impedance element in response to the stimulus signal, and for producing an output signal indicative of the characteristic of the impedance of the complex impedance element; and a signal processing circuit for carrying out a Fast Fourier Transform on the output signal to produce a further output signal for use in characterization of the impedance of the complex impedance element. - View Dependent Claims (54, 55, 56, 57, 58)
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Specification