Frequency shift keying signaling for integrated circuits
First Claim
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1. A system for communicating between two integrated circuits, comprising:
- a first integrated circuit having a transmitter circuit for converting digital data into a frequency modulated signal, the first integrated circuit positioned on a first printed circuit board for transmission of the frequency modulated signal via a transmission line to a second integrated circuit;
the frequency modulated signal representing the digital data as the frequency modulated signal includes signal components having frequencies representing logic states of the digital data;
the second integrated circuit electrically coupled to the transmission line and having a receiver circuit for converting the frequency modulated signal back to the digital data, the second integrated circuit positioned on the first printed circuit board or on a second printed circuit board, wherein the second printed circuit board is connected to the first printed circuit board via a common backplane;
the frequency modulated signal including an amplitude frequency shift keying (AFSK) signal the modulation circuit comprising;
a frequency generator configured to generate a plurality of clock signals, each clock signal of the plurality of clock signals having a predetermined frequency;
a modulation circuit configured to receive the digital data and at least one of the plurality of clock signals and configured to generate the AFSK signal;
a first multiplexer configured to select a clock signal of the plurality of clock signals using a first bit of the digital data;
an amplifier connected to the first multiplexer for amplifying the selected clock signal; and
a second multiplexer connected to the amplifier and configured to select the selected clock signal, the second multiplexer controlled by a second bit of the digital data.
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Abstract
The present invention relates to a system for communicating between two integrated circuits (ICs) or within an IC. The ICs are either on the same circuit boards or on different circuit boards with a common backplane. A first integrated circuit has transmitter circuit that generates frequency shift keying signals using digital data and a second integrated circuit has a receiver circuit for recovering the digital data from the frequency shift keying signals.
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Citations
22 Claims
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1. A system for communicating between two integrated circuits, comprising:
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a first integrated circuit having a transmitter circuit for converting digital data into a frequency modulated signal, the first integrated circuit positioned on a first printed circuit board for transmission of the frequency modulated signal via a transmission line to a second integrated circuit; the frequency modulated signal representing the digital data as the frequency modulated signal includes signal components having frequencies representing logic states of the digital data; the second integrated circuit electrically coupled to the transmission line and having a receiver circuit for converting the frequency modulated signal back to the digital data, the second integrated circuit positioned on the first printed circuit board or on a second printed circuit board, wherein the second printed circuit board is connected to the first printed circuit board via a common backplane; the frequency modulated signal including an amplitude frequency shift keying (AFSK) signal the modulation circuit comprising; a frequency generator configured to generate a plurality of clock signals, each clock signal of the plurality of clock signals having a predetermined frequency; a modulation circuit configured to receive the digital data and at least one of the plurality of clock signals and configured to generate the AFSK signal; a first multiplexer configured to select a clock signal of the plurality of clock signals using a first bit of the digital data; an amplifier connected to the first multiplexer for amplifying the selected clock signal; and a second multiplexer connected to the amplifier and configured to select the selected clock signal, the second multiplexer controlled by a second bit of the digital data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for communicating between two integrated circuits, comprising:
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transforming digital data from a first integrated circuit into a frequency modulated signal for transmission of the frequency modulated signal via a transmission line to a second integrated circuit;
the first integrated circuit being positioned on a first printed circuit board;the frequency modulated signal representing the digital data as the frequency modulated signal includes signal components having frequencies representing logic states of the digital data; transmitting the frequency modulated signal to the second integrated circuit electrically coupled to the transmission line, the second integrated circuit being positioned on the first printed circuit board or on a second printed circuit board, wherein the second printed circuit board is connected to the first printed circuit board via a common backplane; recovering the digital data from the frequency modulated signal in the second integrated circuit; the frequency modulated signal comprises an amplitude frequency shift keying (AFSK) signal, wherein the AFSK signal is formed by a modulation circuit comprising;
a first multiplexer configured to select a clock signal of a plurality of clock signals using a first bit of the digital data;
an amplifier connected to the first multiplexer for amplifying the selected clock signal; and
a second multiplexer connected to the amplifier and configured to select the selected clock signal, the second multiplexer being controlled by a second bit of the digital data signal; andthe recovering including; demodulating the frequency modulated signal to produce a plurality of intermediary bits; and mapping the plurality of intermediary bits to the digital data. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A system for communicating data between a plurality of components in an integrated circuit, comprising:
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a first component of the plurality of components having an output circuit for converting digital data of the first component into a frequency modulated signal, wherein the output circuit comprises;
a first multiplexer configured to select a clock signal of a plurality of clock signals using a first bit of the digital data;
an amplifier connected to the first multiplexer for amplifying the selected clock signal; and
a second multiplexer connected to the amplifier and configured to select the selected clock signal, the second multiplexer being controlled by a second bit of the digital data signal;the frequency modulated signal representing the digital data as the frequency modulated signal includes signal components having frequencies representing logic states of the digital data; a second component of the plurality of components having an input circuit for converting the frequency modulated signal back to the digital data, wherein the input circuit comprises a multiplexer configured to select the selected clock signal; and an electrical connection in the integrated circuit coupled to the first component and the second component for communicating between the input and the output circuits; the input circuit including; a frequency detection circuit having a counter circuit configured to determine an indication of a number of edges of the frequency modulated signal; and a mapping circuit having digital logic for receiving the indication and generating at least one bit of the digital data. - View Dependent Claims (19, 20, 21)
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22. A system for communicating data between two integrated circuits, comprising:
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a means for transforming digital data from a first integrated circuit into a frequency modulated signal, the first integrated circuit positioned on a first printed circuit board for transmission of the frequency modulated signal via a transmission line to a second integrated circuit, and wherein the means for transforming digital data includes a means for generating a plurality of clock signals with different frequencies; the frequency modulated signal representing the digital data as the frequency modulated signal includes signal components having the frequencies representing logic states of the digital data; the second integrated circuit being positioned on the first printed circuit board or on a second printed circuit board and electrically coupled to the transmission line, wherein the second printed circuit board is connected to the first printed circuit board via a common backplane; a means in the second integrated circuit for recovering the digital data from the frequency modulated signal; and wherein the frequency modulated signal comprises an amplitude frequency shift keying (AFSK) signal wherein the AFSK signal is formed by a modulation circuit comprising;
a first multiplexer configured to select a clock signal of a plurality of clock signals using a first bit of the digital data;
an amplifier connected to the first multiplexer for amplifying the selected clock signal; and
a second multiplexer connected to the amplifier and configured to select the selected clock signal, the second multiplexer being controlled by a second bit of the digital data signal;the means in the second integrated circuit for recovering the digital data including; a frequency detection circuit having a counter circuit configured to determine an indication of a number of edges of the frequency modulated signal; and a mapping circuit having digital logic for receiving the indication and generating at least one bit of the digital data.
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Specification