Patent EP0853374A1 successfully refreshed from Google Patents.
EP0853374A1
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EP
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Image reject mixer
Assignee: Microchip Technology Caldicot Ltd
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Filing: 1997-12-16
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Granted: —
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Expires: 2017-12-16
Abstract
Abstract Circuit 200 comprises an input amplifier stage 290, phase-splitters 292, 293 and mixer cores 294, 295. An input signal is applied to terminal 220, a local oscillator signal applied to terminals 230, 231 and a 90° shifted local oscillator signal is applied to terminals 232, 233. The In-phase differential signal is output at terminals 240, 241 and the quadrature signal is output at terminals 240, 233. Phase-splitters 292, 293 comprise base-coupled transistors 202, 203, 205, 206 which are biased by a potential applied to terminal 262. As these phase-splitters are driven by input amplifier stage 290, which acts as a current source, the arrangement has very good noise properties. Degeneration inductor 280 reduces the noise figure of the circuit further because it is a noiseless component. Phase-splitters 292, 293 and mixer cores 294, 295 are preferably cross-coupled to allow cancellation in phase-splitters 292, 293 of the second harmonic of the local oscillator signal generated at the inputs to mixer cores 294, 295.
Inventors
- 👤 Viatcheslav Igor Souetinov
- 👤 Tak Kwong Chan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 16:28
CPC Classifications
H; H03; H03D; H03D7/00; H03D7/14; H03D7/1425; H03D7/1433; H03D7/1441; H03D7/1458; H03D7/1491; H03D7/16; H03D7/165; H03D2200/00; H03D2200/0001; H03D2200/0019; H03D2200/0041; H03D2200/0082; H03D7/12; H03D7/125; H03D7/18
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
70 words
An image reject mixer circuit arrangement comprising an input amplifier connected
to first and second phase-splitters, the phase-splitters each having two substantially
complementary outputs in which a first mixer core is arranged to mix two of said phase-splitter
outputs with an oscillatory signal and a second mixer core is arranged to mix the
other two of said phase splitter outputs with a signal obtained by phase shifting the
oscillatory signal.
Claim 2
Dependent Claim
32 words
An image reject mixer circuit arrangement in accordance with Claim 1 in which
the complementary outputs of the first and second phase-splitters are cross- coupled with
the first and second mixer cores.
Claim 3
Dependent Claim
56 words
An image reject mixer circuit arrangement in accordance with either preceding
claim in which the first phase-splitter comprises first and second transistors having their
control electrodes connected together and to a first current source potential and the second
phase-splitter comprises third and fourth transistors having their control electrodes
connected together and to a second current source.
Claim 4
Dependent Claim
56 words
An image reject mixer circuit arrangement in accordance with Claim 3 in which
the first main electrode of each of the first and second transistors forms the substantially
complementary outputs of the first phase-splitter and the first main electrode of each of
the third and fourth transistors form the substantially complementary outputs of the second
phase-splitter.
Claim 5
Dependent Claim
44 words
An image reject mixer circuit arrangement in accordance with any preceding claim
in which the input amplifier comprises an input transistor having its control electrode
arranged to receive an input signal and its first main electrode connected to both the first
and second phase-splitters.
Claim 6
Dependent Claim
40 words
An image reject mixer circuit arrangement in accordance with Claim 5 in which
the control electrode of the fifth transistor is connected via a resistor to a first bias
potential and receives the input signal through a dc blocking capacitor.
Claim 7
Dependent Claim
32 words
An image reject mixer circuit arrangement in accordance with Claim 5 or Claim
6 in which an inductor is connected between the second main electrode of the fifth
transistor and ground potential.
Claim 8
Dependent Claim
30 words
An image reject mixer circuit arrangement in accordance with Claim 7 in which
the inductor is formed partly from at least one of bonding wires, connecting pins and IC
packaging.
Claim 9
Dependent Claim
63 words
An image reject mixer circuit arrangement in accordance with Claim 4 and Claim
5 or any claim appended to both Claim 4 and Claim 5 in which the first main electrode
of the fifth transistor is connected to the second main electrode of the first transistor and
of the third transistor thereby to connect the input amplifier to the first and second phase-splitters.
Claim 10
Dependent Claim
46 words
An image reject mixer circuit arrangement in accordance with Claim 4 and Claim
5 or any claim appended to both Claim 4 and Claim 5 in which the second main electrode
of both the second transistor and the fourth transistor are connected to a current source.
Claim 11
Dependent Claim
32 words
An image reject mixer circuit arrangement in accordance with Claim 10 in which
the second transistor and the fourth transistor have their respective second main electrodes
connected to a common current source.
Claim 12
Dependent Claim
54 words
An image reject mixer circuit arrangement in accordance with Claim 11 in which
the second and fourth transistors are connected to the first main electrode of a sixth
transistor, the sixth transistor having its control electrode connected to a second bias
potential via a resistor and its second main electrode connected to ground potential.
Claim 13
Dependent Claim
31 words
An image reject mixer circuit arrangement in accordance with Claim 12 in which
an ac grounding capacitor is connected between the first main electrode of the sixth
transistor and ground potential.
Claim 14
Dependent Claim
55 words
An image reject mixer circuit arrangement in accordance with any of Claims 9 to
13 in which the first main electrode of the fifth transistor is connected to the first and
second phase-splitters by a feedback resistor and the control and first main electrodes of
the fifth transistor are connected together by a feedback capacitor.
Claim 15
Dependent Claim
36 words
An image reject mixer circuit arrangement in accordance with Claim 4 or any claim
appended thereto in which the outputs of the first and second phase-splitters are connected
to ground potential each by a filtering capacitor.
References Cited (Backward Citations)
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