Direct conversion receiver especially suitable for frequency shift keying (FSK) modulated signals
First Claim
1. A direct conversion receiver especially suitable for providing direct conversion of an input FSK-modulated radio--frequency signal of a predetermined carrier frequency, and for separating the input radio-frequency signal into two signals by using signals with a phase difference of π
- /2 of the carrier frequency, the direct conversion receiver comprising;
a) local oscillator means for generating a local oscillation signal having a frequency substantially equal to the carrier frequency and a magnitude small enough not to cause substantial electromagnetic interference with adjacent receivers; and
b) a semiconductor integrated circuit including;
1) amplification circuit means for amplifying the small-magnitude local oscillation signal provided through at least one lead from outside the semiconductor integrated circuit, and for providing an amplified oscillation signal; and
2) mixer unit means for mixing (i) the amplified oscillation signal and (ii) a radio frequency signal corresponding to the input radio-frequency signal, and for outputting from the semiconductor integrated circuit an integrated circuit mixed output signal;
wherein the amplification circuit means within the semiconductor integrated circuit allows the local oscillation signal to be small enough so as not to cause substantial electromagnetic interference with the adjacent receivers, without the necessity of providing substantial additional shielding for the local oscillator means or the at least one lead.
1 Assignment
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Accused Products
Abstract
A direct conversion receiver for providing a direct conversion of a radio frequency signal having a carrier frequency comprises a local oscillator for substantially equal frequency to the carrier, and a semiconductor integrated circuit mounting mixers and amplifiers for amplifying inputs to the mixer. The amplifiers amplify the local oscillation signals and/or radio frequency signal inputted from the outside of the semiconductor integrated circuit and supply the amplified signals to the mixers. The mixers mix these inputted signals and output the mixed signals to the outside of the semiconductor integrated circuit. By thus forming the receiver, radiation of the local oscillation signals to outside of the receiver and leakage inside thereof can be suppressed.
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Citations
3 Claims
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1. A direct conversion receiver especially suitable for providing direct conversion of an input FSK-modulated radio--frequency signal of a predetermined carrier frequency, and for separating the input radio-frequency signal into two signals by using signals with a phase difference of π
- /2 of the carrier frequency, the direct conversion receiver comprising;
a) local oscillator means for generating a local oscillation signal having a frequency substantially equal to the carrier frequency and a magnitude small enough not to cause substantial electromagnetic interference with adjacent receivers; and b) a semiconductor integrated circuit including; 1) amplification circuit means for amplifying the small-magnitude local oscillation signal provided through at least one lead from outside the semiconductor integrated circuit, and for providing an amplified oscillation signal; and 2) mixer unit means for mixing (i) the amplified oscillation signal and (ii) a radio frequency signal corresponding to the input radio-frequency signal, and for outputting from the semiconductor integrated circuit an integrated circuit mixed output signal; wherein the amplification circuit means within the semiconductor integrated circuit allows the local oscillation signal to be small enough so as not to cause substantial electromagnetic interference with the adjacent receivers, without the necessity of providing substantial additional shielding for the local oscillator means or the at least one lead. - View Dependent Claims (2, 3)
- /2 of the carrier frequency, the direct conversion receiver comprising;
Specification