Sequential DC offset correction for amplifier chain
First Claim
1. An amplifier chain comprising:
- a) a first amplifier, b) a first track and hold circuit, coupled to the first amplifier and having a tracking state and a holding state;
c) a second amplifier, coupled to the first amplifier;
d) a second track and hold circuit, coupled to the second amplifier and having a tracking state and a holding state; and
e) a control circuit which generates a control signal, coupled to the first track and hold circuit and to the second track and hold circuit, the control signal configured to set the first track and hold circuit to the tracking state and to set the second track and hold circuit to the tracking state, and to sequentially set the first track and hold circuit to the holding state and then set the second track and hold circuit to the holding state.
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0 Petitions
Accused Products
Abstract
An amplifier chain with sequential DC offset correction for use in a radio receiver is provided. The amplifier chain has at least first and second amplifier stages connected in series. The first and second stages include an amplifier and a track and hold circuit connected in parallel across the amplifier. The track and hold circuit has a tracking state and a holding state. A control signal is coupled to the track and hold circuits of the first and second stages. The control signal is configured to set the track and hold circuits to the tracking state, which may be done simultaneously, and to sequentially set the track and hold circuit of the first stage to the holding state and then set the track and hold circuit of the second stage to the holding state.
21 Citations
22 Claims
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1. An amplifier chain comprising:
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a) a first amplifier, b) a first track and hold circuit, coupled to the first amplifier and having a tracking state and a holding state;
c) a second amplifier, coupled to the first amplifier;
d) a second track and hold circuit, coupled to the second amplifier and having a tracking state and a holding state; and
e) a control circuit which generates a control signal, coupled to the first track and hold circuit and to the second track and hold circuit, the control signal configured to set the first track and hold circuit to the tracking state and to set the second track and hold circuit to the tracking state, and to sequentially set the first track and hold circuit to the holding state and then set the second track and hold circuit to the holding state. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An amplifier for use in a radio receiver having a mixer, which generates an in-phase mixer output and a quadrature phase mixer output, the amplifier comprising:
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a) an in-phase amplifier chain, coupled to the in-phase mixer output, the in phase amplifier chain including;
1) a first amplifier coupled to a first track and hold circuit;
2) a second amplifier coupled in series with the first amplifier, the second amplifier coupled to a second track and hold circuit; and
b) a quadrature phase amplifier chain, coupled to the quadrature phase mixer output, the quadrature phase amplifier chain including;
1) a third amplifier coupled to a third track and hold circuit;
2) a fourth amplifier coupled in series with the third amplifier and coupled to a fourth track and hold circuit; and
c) a control circuit which generates a control signal coupled to the first, second, third and fourth track and hold circuits, the control signal configured to set the first, second, third and fourth track and hold circuits to a tracking state, and configured to sequentially set the first track and hold circuit, to a holding state and set the second track and hold circuit to a holding state, and to sequentially set the third track and hold circuit to a holding state and set the fourth track and hold circuit to a holding state. - View Dependent Claims (9)
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10. An amplifier chain comprising:
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a) first means for amplifying;
b) first means for correcting DC offset coupled to the first means for amplifying, the first means for correcting DC offset further having a tracking state and a holding state;
c) a second means for amplifying, coupled to the first means for amplifying;
d) a second means for correcting DC offset coupled to the second means for amplifying the second means for correcting DC offset having a tracking state and a holding state; and
e) means for controlling the states of the first means for correcting DC offset and the second means for correcting DC offset, the means for controlling further comprising a means for setting the first means for correcting DC offset to the tracking state, for setting the second means for correcting DC offset to the tracking state, and for sequentially setting the first means for correcting DC offset to the holding state and setting the second means for correcting DC offset to the holding state. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for correcting DC offset in an amplifier chain having at least first and second amplifiers coupled in series, each amplifier being coupled to a track and hold circuit having a tracking state and a holding state, comprising:
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a) setting a first track and hold circuit to the tracking state;
b) setting a second track and hold circuit to the tracking state;
c) setting the first track and hold circuit to the holding state; and
d) setting the second track and hold circuit to the holding state after setting the first track and hold circuit to the holding state;
wherein the second track and hold circuit is subsequent to the first track and hold circuit in the amplifier chain. - View Dependent Claims (18, 19)
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20. A method for correcting DC offset in a radio circuit prior to a time slot in a time division multiplex format, the radio circuit having at least first and second amplifier stages, the method comprising:
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a) turning on at least a portion or the radio circuit at a first time prior to the timeslot;
b) activating tracking of the DC offset in at least the first and second amplifier stages after the first time and before the timeslot;
c) activating a holding state to hold the DC offset of at least the first and second amplifier stages at a time after tracking is activated and before the timeslot;
d) enabling the radio frequency amplifier at a time before the timeslot, but occurring after activating the holding state. - View Dependent Claims (21, 22)
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Specification