Correcting circuit for mixing circuit receiver using same and frequency spectrum inverting circuit using same
First Claim
1. A double superheterodyne receiver comprising:
- a pair of first mixer circuits connected in an orthogonal relation to each other and acting to convert a received RF signal into first intermediate-frequency signals in a baseband;
a pair of second mixer circuits connected in an orthogonal relation to each other and acting to convert said first intermediate-frequency signals into second intermediate-frequency signals of a desired center frequency;
a demodulator circuit for arithmetically combining said second intermediate-frequency signals so as to create a third intermediate-frequency signal and for a demodulating an original signal from said third intermediate-frequency signal; and
,a pair of detector circuits receiving output signals from said pair of second mixer circuits and acting to detect a leaking carrier component contained in said output signals from said pair of second mixer circuits, said detector circuits producing output signals having the same phase as said leaking carrier component, wherein said output signals from said detector circuits are provided to said pair of second mixer circuits to correct DC balance between said pair of second mixer circuits so that said leaking carrier component is reduced.
1 Assignment
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Accused Products
Abstract
A double superheterodyne receiver comprising a pair of first mixer circuits, a pair of second mixer circuits, a demodulator circuit, and a pair of detector circuits. The first mixer circuits are connected in an orthogonal relation to each other and acts to convert a received RF signal into a pair of first intermediate-frequency (IF) signals in the baseband. The second mixer circuits are connected in an orthogonal relation to each other and acts to convert the first IF signals into a pair of second IF signals of a given center frequency. The demodulator circuit arithmetically combines the second IF signals so as to create a third IF signal, and demodulates the original signal from the third IF signal. The output signals from the second mixer circuits are supplied to the detector circuits, which in turn detect the carrier component contained in the output signals. The output signals from the detector circuits are fed to the second mixer circuits. The DC balance between the second mixer circuits is so corrected that the leaking carrier components are reduced.
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Citations
14 Claims
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1. A double superheterodyne receiver comprising:
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a pair of first mixer circuits connected in an orthogonal relation to each other and acting to convert a received RF signal into first intermediate-frequency signals in a baseband; a pair of second mixer circuits connected in an orthogonal relation to each other and acting to convert said first intermediate-frequency signals into second intermediate-frequency signals of a desired center frequency; a demodulator circuit for arithmetically combining said second intermediate-frequency signals so as to create a third intermediate-frequency signal and for a demodulating an original signal from said third intermediate-frequency signal; and
,a pair of detector circuits receiving output signals from said pair of second mixer circuits and acting to detect a leaking carrier component contained in said output signals from said pair of second mixer circuits, said detector circuits producing output signals having the same phase as said leaking carrier component, wherein said output signals from said detector circuits are provided to said pair of second mixer circuits to correct DC balance between said pair of second mixer circuits so that said leaking carrier component is reduced. - View Dependent Claims (2, 3, 4)
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5. A double superheterodyne receiver comprising:
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a pair of first mixer circuits connected in an orthogonal relation to each other and acting to convert a received RF signal into a pair of first intermediate-frequency signals in a baseband; a pair of second mixer circuits connected in an orthogonal relation to each other and acting to convert said first intermediate-frequency signals into second intermediate-frequency signals of a desired center frequency; a demodulator circuit for arithmetically combining said second intermediate-frequency signals so as to create a third intermediate-frequency signal and for demodulating an original signal from said third intermediate-frequency signal, wherein at least said first mixer circuits and said demodulator circuit are formed on an integrated circuit; and
,a pair of detector circuits receiving output signals from said second mixer circuits and acting to detect a leaking carrier component contained in said output signals from said second mixer circuits, said detector circuits producing output signals having the same phase as said leaking carrier component, wherein said output signals from said detector circuits are provided to said second mixer circuits to correct DC balance between said second mixer circuits in such a way that said leaking carrier component is reduced. - View Dependent Claims (6, 7)
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8. A circuit for inverting a frequency spectrum, comprising:
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a carrier signal-generating circuit for producing a carrier signal; a balanced modulator circuit receiving said carrier signal from said carrier signal-generating circuit and an audio signal as a modulating input signal, said audio signal having a limited bandwidth; and
,a detector circuit receiving an output signal from said balanced modulator circuit and acting to detect a leaking carrier component contained in said output signal from said balanced modulator circuit, said detector circuit producing an output signal having the same phase as said leaking carrier component, wherein said output signal from said detector circuit is provided to said balanced modulator circuit to correct DC balance in said balanced modulator circuit in such a way that said leaking carrier component decreases. - View Dependent Claims (9, 10, 11)
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12. A correcting circuit for a mixer circuit, comprising:
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a double balanced modulator circuit receiving a carrier signal and acting to convert a frequency of an input signal into a second frequency and to produce a first output signal of said second frequency; and
,a detector circuit receiving said output signal from said double balanced modulator circuit and acting to detect a leaking carrier component contained in said output signal, said detector circuit producing an output signal having the same phase as said leaking carrier component, wherein said output signal from said detector circuit is provided to said double balanced modulator circuit to correct DC balance in said double balanced modulator circuit in such a way that said leaking carrier component decreases. - View Dependent Claims (13, 14)
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Specification