Low-power, noise insensitive communication channel using logarithmic detector amplifier (LDA) demodulator
First Claim
1. A low-power, noise insensitive communication channel comprising:
- a first device comprising;
a first modulator having an input to accept a baseband signal with encoded information, and an output to supply a modulated signal having a first carrier frequency, including the encoded information;
a first interface connected to a hardwire transmission medium to supply the modulated signal;
a second device comprising;
a second interface connected to the hardline transmission medium;
a first logarithmic detector amplifier (LDA) demodulator circuit having an input connected to the second interface, and an output to supply the baseband signal with the encoded information; and
,wherein the LDA demodulator circuit comprises a frequency-to-voltage converter (FVC) to accept a series of second frequency pulses having a rate of change at least twice that of an encoded information rate, and converts the series of second frequency pulses to a series of voltage levels at the encoded information rate.
1 Assignment
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Accused Products
Abstract
A method is provided for communicating signals at a low power level in an electromagnetic interference (EMI) environment. A first device transmits a modulated signal having a first carrier frequency, including the encoded information via a hardwire transmission medium. In one aspect, the power level of the modulated signal can be adjusted to minimize power consumption or reduce the generation of EMI. The modulated signal may be in one of the following formats: frequency modulation (FM) or phase modulation (PM) to name a few examples. A second device including a logarithmic detector amplifier (LDA) demodulator circuit receives the signal, which may be mixed with EMI. The LDA demodulator circuit amplifies the modulated signal, without amplifying the EMI, to supply a demodulated baseband signal, which may be an n-ary digital signal, or an audio signal. A low-power, noise insensitive communication channel is also provided.
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Citations
29 Claims
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1. A low-power, noise insensitive communication channel comprising:
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a first device comprising; a first modulator having an input to accept a baseband signal with encoded information, and an output to supply a modulated signal having a first carrier frequency, including the encoded information; a first interface connected to a hardwire transmission medium to supply the modulated signal; a second device comprising; a second interface connected to the hardline transmission medium; a first logarithmic detector amplifier (LDA) demodulator circuit having an input connected to the second interface, and an output to supply the baseband signal with the encoded information; and
,wherein the LDA demodulator circuit comprises a frequency-to-voltage converter (FVC) to accept a series of second frequency pulses having a rate of change at least twice that of an encoded information rate, and converts the series of second frequency pulses to a series of voltage levels at the encoded information rate. - View Dependent Claims (2, 3, 8, 9, 10)
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4. The communication channel of claim wherein, the first device further comprises:
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a second LDA demodulator circuit having an input and an output; and
,a first switch having an input connected to the first interface, a first switch position connected to the input of the second LDA demodulator circuit, a second switch position connected to the first modulator output, and a control input to accept a first control signal selectively connecting the first switch input to a switch position. - View Dependent Claims (5)
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6. The communication channel of claim wherein the first modulator is an LDA-VCO comprising:
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an amplifier having an input and an output; a capacitor connected between the amplifier input and output; a variable direct current (DC) bias source connected to the amplifier input, responsive to the baseband signal; a first parallel resonant circuit connected between the amplifier output and a reference voltage, having a resonance at the first frequency; and
,wherein the amplifier output supplies a signal centered at the first frequency and modulated in response to the variable bias source.
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7. The communication channel of claim wherein the modulator is an LDA-VCO further comprising:
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an amplifier having an input and an output; a capacitor connected between the amplifier input and output; a DC bias source connected to the amplifier input; a first parallel resonant circuit connected between the amplifier output and a reference voltage, having a resonance at the first frequency; a varicap connected in parallel with the first parallel resonant circuit, to accept a variable tuning voltage responsive to the baseband signal; and
,wherein the amplifier output supplies a signal centered at the first frequency and modulated in response to the variable tuning voltage.
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11. A method for communicating signals at a low power level in an electromagnetic interference (EMI) environment, the method comprising:
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a first device transmitting a modulated signal having a first carrier frequency, including encoded information, via a hardwire transmission medium; the hardwire transmission medium being exposed to an environment comprising EMI; the EMI combining with the modulated signal on the hardwire transmission line to create a mixed signal; a second device including a logarithmic detector amplifier (LDA) demodulator circuit receiving the mixed signal; the LDA demodulator circuit amplifying the modulated signal, without amplifying the EMI; the LDA demodulator circuit supplying a demodulated baseband signal as follows; converting the modulated signal to a series of second frequency pulses having a rate of change at least twice that of an encoded information rate; and
,converting the series of second frequency pulses to a series of voltage levels at the encoded information rate. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method for communicating signals at low power levels, the method comprising:
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at a first time, a first device transmitting a baseband signal with encoded information via a first hardwire transmission medium; at the first time, a second device successfully receiving the baseband signal when it is transmitted at a minimally sufficient first power level, or greater; at a second time, the first device modulating the baseband signal, creating a modulated signal having a first carrier frequency, including the encoded information; at the second time, the first device transmitting the modulated signal, via the hardware first transmission medium, to the second device at a second power level, less than the first power level; and
,at the second time, the second device using a logarithmic detector amplifier (LDA) demodulator circuit to successfully convert the modulated signal to the baseband signal. - View Dependent Claims (20, 21, 22, 23)
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24. A low-power, noise insensitive communication channel comprising:
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a first device comprising; a first modulator having an input to accept a baseband signal with encoded information, and an output to supply a modulated signal having a first carrier frequency, including the encoded information; a first interface connected to a hardwire transmission medium to supply the modulated signal; a second device comprising; a second interface connected to the hardline transmission medium; a first logarithmic detector amplifier (LDA) demodulator circuit having an input connected to the second interface, and an output to supply the baseband signal with the encoded information; and
,wherein the first modulator is a voltage controlled oscillator (VCO) accepting an n-ary logic digital signal, and supplying an n-frequency shift keying (n-FSK) modulated FM signal; and
,wherein the first LDA demodulator circuit supplies the n-ary logic digital signal.
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25. A low-power, noise insensitive communication channel comprising:
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a first device comprising; a first modulator having an input to accept a baseband signal with encoded information, and an output to supply a modulated signal having a first carrier frequency, including the encoded information; a first interface connected to a hardwire transmission medium to supply the modulated signal; a second device comprising; a second interface connected to the hardline transmission medium; a first logarithmic detector amplifier (LDA) demodulator circuit having an input connected to the second interface, and an output to supply the baseband signal with the encoded information; and
,wherein the first device further comprises; a second LDA demodulator circuit having an input and an output; and
,a first switch having an input connected to the first interface, a first switch position connected to the input of the second LDA demodulator circuit, a second switch position connected to the first modulator output, and a control input to accept a first control signal selectively connecting the first switch input to a switch position. - View Dependent Claims (26)
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27. A low-power, noise insensitive communication channel comprising:
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a first device comprising; a first modulator having an input to accept a baseband signal with encoded information, and an output to supply a modulated signal having a first carrier frequency, including the encoded information; a first interface connected to a hardwire transmission medium to supply the modulated signal; a second device comprising; a second interface connected to the hardline transmission medium; a first logarithmic detector amplifier (LDA) demodulator circuit having an input connected to the second interface, and an output to supply the baseband signal with the encoded information; and
,wherein the first modulator is an LDA-VCO comprising; an amplifier having an input and an output; a capacitor connected between the amplifier input and output; a variable direct current (DC) bias source connected to the amplifier input, responsive to the baseband signal; a first parallel resonant circuit connected between the amplifier output and a reference voltage, having a resonance at the first frequency; and
,wherein the amplifier output supplies a signal centered at the first frequency and modulated in response to the variable bias source.
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28. A low-power, noise insensitive communication channel comprising:
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a first device comprising; a first modulator having an input to accept a baseband signal with encoded information, and an output to supply a modulated signal having a first carrier frequency, including the encoded information; a first interface connected to a hardwire transmission medium to supply the modulated signal; a second device comprising; a second interface connected to the hardline transmission medium; a first logarithmic detector amplifier (LDA) demodulator circuit having an input connected to the second interface, and an output to supply the baseband signal with the encoded information; wherein the modulator is an LDA-VCO further comprising; an amplifier having an input and an output; a capacitor connected between the amplifier input and output; a DC bias source connected to the amplifier input; a first parallel resonant circuit connected between the amplifier output and a reference voltage, having a resonance at the first frequency; a varicap connected in parallel with the first parallel resonant circuit, to accept a variable tuning voltage responsive to the baseband signal; and
,wherein the amplifier output supplies a signal centered at the first frequency and modulated in response to the variable tuning voltage.
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29. A method for communicating signals at a low power level in an electromagnetic interference (EMI) environment, the method comprising:
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a first device transmitting an n-frequency shift keying (n-FSK) modulated FM signal having a first carrier frequency, including encoded information, via a hardwire transmission medium; the hardwire transmission medium being exposed to an environment comprising EMI; the EMI combining with the modulated signal on the hardwire transmission line to create a mixed signal; a second device including a logarithmic detector amplifier (LDA) demodulator circuit receiving the mixed signal; the LDA demodulator circuit amplifying the modulated signal, without amplifying the EMI; and
,the LDA demodulator circuit supplying a demodulated baseband signal including log2 (n) streams of baseband binary logic digital signals.
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Specification