Multimode receiver with active blocker suppression
View Patent ↗Various embodiments of a wireless multimode receiver having an off-chip duplex filter associated with a multimode band, and a blocker cancellation circuit disposed on a semiconductor chip are described in the present disclosure.
1. A wireless multimode receiver, comprising:
a duplex filter associated with a multimode band; and
a blocker cancellation circuit disposed on a semiconductor chip and coupled to the duplex filter and configured to reject an unwanted blocker signal from the receiver based on a compensation method employing feed-forward cancellation,
wherein the blocker cancellation circuit comprises a low-noise amplifier (LNA) connected to a first input node of a summing junction and a first RX translational loop connected to a second input node of the summing junction, the blocker cancellation circuit configured to provide feed-forward cancellation of the unwanted blocker signal at an output node of the summing junction using the compensation method to cancel the unwanted blocker signal.
2. The receiver of claim 1 , wherein the blocker cancellation circuit is further configured to select between two different receiving modes operating within the same multimode band.
3. The receiver of claim 2 , wherein the two different receiving modes comprise a GSM receiving mode and a UMTS receiving mode.
4. The receiver of claim 1 , wherein the first RX translational loop comprises a high-pass filter coupled between first and second mixers, the first RX translational loop used by the compensation method for the feed-forward cancellation.
5. The receiver of claim 4 , wherein the first RX translational loop comprises at least two different high-pass filters selectively coupleable between the first and second mixers configured to provide two filtering levels for selecting between two different receiving modes operating within the same multimode band.
6. The receiver of claim 4 , wherein the blocker cancellation circuit comprises a second RX translational loop, wherein the first RX translational loop is configured to cancel unwanted blocker signals using an in-phase RX signal (LO I ), and the second RX translational loop is configured to cancel unwanted blocker signals using the out-of-phase RX signal (LO Q ).
7. The receiver of claim 4 , comprising an antenna selectively coupled to one of a plurality of duplex filters.
8. The receiver of claim 1 , further comprising
a plurality of duplex filters, each duplex filter associated with one of a plurality of multimode bands; and
a plurality of blocker cancellation circuits disposed on a semiconductor die, each blocker cancellation circuit coupled to a corresponding one of the duplex filters.
9. A wireless multimode receiver, comprising:
a plurality of duplex filters, each duplex filter associated with one of a plurality of multimode bands;
an antenna selectively coupled to one of the plurality of duplex filters; and
a plurality of blocker cancellation circuits disposed on a semiconductor die, each blocker cancellation circuit coupled to a corresponding one of the duplex filters and configured to actively reject an unwanted blocker signal from the receiver employing an on-chip filtering technique,
wherein the plurality of blocker cancellation circuits each comprise a low-noise amplifier (LNA) connected to a first input node of a summing junction and a first RX translational loop connected to a second input node of the summing junction, the blocker cancellation circuits configured to provide feed-forward cancellation of the unwanted blocker signal at an output node of the summing junction using the on-chip filtering technique to cancel the unwanted blocker signal.
10. The receiver of claim 9 , wherein the first RX translational loop comprises a high-pass filter coupled between first and second mixers, the first RX translational loop used by the on-chip filtering technique for the feed-forward cancellation.
11. The receiver of claim 10 , wherein the first RX translational loop comprises at least two different high-pass filters selectively coupleable between the first and second mixers configured to provide two filtering levels for selecting between two different receiving modes operating within the same multimode band.
12. The receiver of claim 9 , wherein at least one of the blocker cancellation circuits comprises a power detector connected to an output of the low noise amplifier, configured to activate the filtering only when a strong blocker signal is present to minimize power consumption as a result of filtering.
13. The receiver of claim 9 , wherein each blocker cancellation circuit comprises a second RX translational loop, wherein the first RX translational loop is configured to cancel unwanted blocker signals using an in-phase RX signal (LO I ), and the second RX translational loop is configured to cancel unwanted blocker signals using the out-of-phase RX signal (LO Q ).
14. The receiver of claim 9 , wherein each blocker cancellation circuit is further configured
to receive a receive signal from the antenna by way of one of the plurality of duplex filters, the receive signal comprising first and second receive modes operating within a single frequency band,
to receive an in-phase quadrature signal,
to select between one of the first and second receive modes of the receive signal, and
to actively reject an unwanted blocker signal from the receive signal based on a filtering technique employing feed-forward cancellation.
15. The receiver of claim 14 , wherein the first and second receive modes comprise a GSM receive mode and a UMTS receive mode.
16. A receiver, comprising:
filtering means disposed off-chip, operable to filter a receive signal from an antenna, the receive signal comprising first and second receive modes operating within a single frequency band, and operable to filter a transmit signal supplied to the antenna;
amplification means disposed on-chip, operable to selectively amplify a predetermined frequency band of the receive signal from the antenna and to attenuate frequencies outside the predetermined frequency band; and
blocker cancellation means disposed on-chip, operable
to receive the filtered and amplified receive signal from the antenna,
to receive an in-phase quadrature signal,
to select between the first and second receive modes operating within the same frequency band, and
to actively reject an unwanted blocker signal from the receive signal based on a filtering technique employing feed-forward cancellation,
wherein the blocker cancellation means comprises a low-noise amplifier (LNA) connected to a first input node of a summing junction and a first RX translational loop connected to a second input node of the summing junction, the blocker cancellation means configured to provide feed-forward cancellation of the unwanted blocker signal at an output node of the summing junction using the on-chip filtering technique to cancel the unwanted blocker signal.
17. The receiver of claim 16 , wherein the filtering means comprises a duplex filter coupled between the antenna and the blocker cancellation means for filtering the receive signal during a receive mode, and coupled between a transmit signal means and the antenna for filtering the transmit signal during a transmit mode.
18. A method for rejecting unwanted blocker signals from a receive signal comprising two different receiving modes operating within the same multimode band employing an on-chip filtering technique, the method comprising:
filtering the receive signal comprising first and second receive modes operating within a predetermined frequency band;
amplifying on-chip the predetermined frequency band of the receive signal, and attenuating frequencies outside the predetermined frequency band; and
rejecting an unwanted blocker signal from the receive signal by:
receiving the filtered and amplified receive signal,
receiving an in-phase quadrature signal,
selecting between the first and second receive modes operating within the predetermined frequency band, and
rejecting an unwanted blocker signal from the filtered and amplified receive signal employing a filtering technique based on feed-forward cancellation, wherein rejecting the unwanted blocker signal further comprises:
amplifying the filtered and amplified receive signal that includes the unwanted blocker signal,
downconversion mixing the receive signal with a quadrature local oscillator signal,
high pass filtering the mixed receive signal,
upconvertinq the high-pass filtered signal to remove the desired signal from the receive signal, thereby providing an upconverted blocker signal,
subtracting the u converted blocker signal from the amplified filtered and amplified receive signal, thereby resulting in an amplified desired signal while rejecting the unwanted blocker signal.
19. The method of claim 18 , comprising quadrature demodulating the desired signal to provide a zero or low IF signal.