Waiting circuit
First Claim
1. A waiting circuit incorporated within a portable terminal of a mobile communication system, for detecting a predetermined signal from a base station to start other circuits which are in a sleep mode, said predetermined signal being generated in said base station having a speed corresponding to a predetermined symbol rate, said predetermined signal being modulated in said base station to be an intermediate frequency signal having a frequency higher than a frequency of said symbol rate, comprising:
- a sub-sampling circuit for sampling said intermediate frequency signal in response to a sampling clock having a speed equal to an integer times said symbol rate;
a matched filter for multiplying said sampled intermediate frequency signal by a predetermined sequence of coefficients corresponding to said intermediate frequency signal, and producing a produces a matched filter signal; and
a control circuit for starting said other circuits when said matched filter signal indicates that said predetermined signal is received.
7 Assignments
0 Petitions
Accused Products
Abstract
A waiting circuit which is utilized in a mobile communication system. The waiting circuit detects a predetermined signal from a base station. The waiting circuit starts other circuits in the mobile communication system which are in a sleep mode when the predetermined signal is received. The predetermined signal is generated in the base station. The predetermined signal has a speed equal to a predetermined symbol rate and is modulated to be an intermediate frequency signal. The intermediate frequency signal is sampled in response to a sampling clock that has a speed equal to an integer times the symbol rate. The sampled intermediate frequency signal is input to a match filter which multiplies the sample signal by a predetermined sequence of coefficients.
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Citations
16 Claims
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1. A waiting circuit incorporated within a portable terminal of a mobile communication system, for detecting a predetermined signal from a base station to start other circuits which are in a sleep mode, said predetermined signal being generated in said base station having a speed corresponding to a predetermined symbol rate, said predetermined signal being modulated in said base station to be an intermediate frequency signal having a frequency higher than a frequency of said symbol rate, comprising:
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a sub-sampling circuit for sampling said intermediate frequency signal in response to a sampling clock having a speed equal to an integer times said symbol rate; a matched filter for multiplying said sampled intermediate frequency signal by a predetermined sequence of coefficients corresponding to said intermediate frequency signal, and producing a produces a matched filter signal; and a control circuit for starting said other circuits when said matched filter signal indicates that said predetermined signal is received. - View Dependent Claims (2, 3, 4, 8, 9, 10, 12, 13)
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5. A waiting circuit incorporated within a portable terminal of a mobile communication system, for detecting a predetermined signal from a base station to start other circuit which are in a sleep mode, said predetermined signal being generated in said base station having a speed corresponding to a predetermined symbol rate, said predetermined signal being step-wisely modulated in said base station to be a plurality of intermediate frequency signals being step-wisely higher one after another, an intermediate frequency signal of a final step being modulated by a carrier signal, said waiting circuit comprising:
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a frequency conversion circuit for converting a received signal having a carrier wave frequency into an intermediate frequency signal having the lowest frequency of said plurality intermediate frequency signals; a sub-sampling circuit for sampling said intermediate frequency signal having said lowest frequency in response to a sampling clock having a speed equal to an integer times said symbol rate; a matched filter for multiplying said sampled intermediate frequency signal by a predetermined sequence of coefficients corresponding to said intermediate frequency signal having the lowest frequency, and producing a matched filter signal; and a control circuit for starting said other circuits when said matched filter signal indicates that said predetermined signal is received. - View Dependent Claims (6, 7)
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11. A waiting circuit incorporated within a portable terminal of a mobile communication system, for detecting a predetermined signal from a base station to start other circuits which are in a sleep mode, said predetermined signal being generated in said base station having a speed corresponding to a predetermined signal rate, and is quadratically modulated in said base station into in-phase and quadrature phase components, each of said components being step-wisely modulated in said base station to be a plurality of intermediate frequency signals being step-wisely higher one after another, an intermediate frequency signal of a final step being modulated by a carrier signal, said waiting circuit comprising:
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a frequency conversion circuit for converting a received signal having a carrier wave frequency into an intermediate frequency signal having the lowest frequency of said plurality of intermediate frequency signals; a sub-sampling circuit for sampling said intermediate frequency signal having said lowest frequency in response to two phase sampling clocks each having a speed equal to an integer times said symbol rate, wherein each of said two phase sampling clocks are shifted from each other by a quarter of a cycle of said lowest intermediate frequency; a complex matched filter for multiplying said sampled intermediate frequency signals of both of said sampling clocks by a predetermined sequence of coefficients corresponding to said intermediate frequency signal having said lowest frequency, and producing a complex matched filter signal; and a control circuit for starting said other circuits when said complex matched filter signal indicates that said predetermined signal is received. - View Dependent Claims (14, 15, 16)
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Specification