Single local oscillator in a multi-band frequency division duplex transceiver

Patent metadata

Field	Value
Publication number	US-2020235902-A1
Application number	US-201916272778-A
Country	US
Kind code	A1
Filing date	Feb 11, 2019
Priority date	Jan 17, 2019
Publication date	Jul 23, 2020
Grant date	—

Abstract

Embodiments of the present disclosure relate to multi-band FDD transceivers. An example transceiver includes a LO, configured to generate a LO signal to be shared between a receiver and a transmitter of the transceiver. Both the receiver and the transmitter use quadrature signal processing and are configured to multi-band operation. Sharing a single LO to perform frequency conversion of different frequency bands of received and transmitted signals advantageously allows reducing the number of LOs used in a multi-band FDD transceiver.

First claim

1 . A multi-band frequency division duplex (FDD) transceiver system, comprising:
a local oscillator (LO), configured to provide a LO signal; a receive (RX) quadrature mixer, configured to mix the LO signal with a received radio frequency (RF) signal to generate a downconverted RX signal, where the received RF signal includes a first received signal component in a first band of receiver frequencies and a second received signal component in a second band of receiver frequencies, the second band of receiver frequencies being separate from the first band of receiver frequencies; and a transmit (TX) quadrature mixer, configured to mix the LO signal with a TX signal to generate an upconverted RF TX signal, where the upconverted TX signal includes a first upconverted TX signal component in a first band of transmitter frequencies and a second upconverted TX signal component in a second band of transmitter frequencies, the second band of transmitter frequencies being separate from each one of the first band of transmitter frequencies, the first band of receiver frequencies, and the second band of receiver frequencies.

2 . The multi-band FDD transceiver system according to claim 1 , wherein a frequency of the LO signal is within the first band of receiver frequencies.

3 . The multi-band FDD transceiver system according to claim 1 , wherein a frequency of the LO signal is within the first band of transmitter frequencies.

4 . The multi-band FDD transceiver system according to claim 1 , wherein:
the downconverted RX signal includes an in-phase RX signal component and a quadrature RX signal component, and the RX quadrature mixer includes a first RX path mixer and a second RX path mixer, where
the first RX path mixer is configured to generate the in-phase RX signal component based on the received RF signal and an in-phase component of the LO signal, and
the second RX path mixer is configured to generate the quadrature RX signal component based on the received RF signal and a quadrature component of the LO signal.

5 . The multi-band FDD transceiver system according to claim 4 , further comprising:
a first analog-to-digital converter (ADC), configured to convert the in-phase RX signal component to a digital in-phase RX signal component; and a second ADC, configured to convert the quadrature RX signal component to a digital quadrature RX signal component.

6 . The multi-band FDD transceiver system according to claim 5 , further comprising:
a first filter, having an input coupled to an output of the first RX path mixer, and having an output coupled to an input of the first ADC; and a second filter, having an input coupled to an output of the second RX path mixer, and having an output coupled to an input of the second ADC.

7 . The multi-band FDD transceiver system according to claim 1 , wherein:
the upconverted TX signal includes an in-phase upconverted TX signal component and a quadrature upconverted TX signal component, and the TX quadrature mixer includes a first TX path mixer and a second TX path mixer, where
the first TX path mixer is configured to generate the in-phase upconverted TX signal component based on the TX signal and an in-phase component of the LO signal, and
the second TX path mixer is configured to generate the quadrature upconverted TX signal component based on the TX signal and a quadrature component of the LO signal.

8 . The multi-band FDD transceiver system according to claim 7 , further comprising:
a first digital-to-analog converter (DAC), configured to convert a digital in-phase TX signal component to an analog in-phase TX signal component, where the first TX path mixer is configured to generate the in-phase upconverted TX signal component based on the analog in-phase TX signal component; and a second DAC, configured to convert a digital quadrature TX signal component to an analog quadrature TX signal component, where the second TX path mixer is configured to generate the quadrature upconverted TX signal component based on the analog quadrature TX signal component.

9 . The multi-band FDD transceiver system according to claim 8 , further comprising:
a first filter, having an input coupled to an output of the first DAC, and having an output coupled to an input of the first TX path mixer; and a second filter, having an input coupled to an output of the second DAC, and having an output coupled to an input of the second TX path mixer.

10 . The multi-band FDD transceiver system according to claim 1 , wherein:
the RX quadrature mixer mixing the LO signal with the received RF signal includes the RX quadrature mixer performing a quadrature downconversion to generate the downconverted RX signal, and the TX quadrature mixer mixing the LO signal with the TX signal includes the TX quadrature mixer performing a quadrature upconversion to generate the upconverted TX signal.

11 . The multi-band FDD transceiver system according to claim 1 , wherein a difference between a frequency of the LO signal and a smallest frequency of the received RF signal is less than 160 megahertz.

12 . The multi-band FDD transceiver system according to claim 1 , wherein a difference between a frequency of the LO signal and a largest frequency of the upconverted TX signal is less than 120 megahertz.

13 . The multi-band FDD transceiver system according to claim 1 , further including:
a further LO, configured to provide a further LO signal; a further TX path mixer, configured to mix the further LO signal with a further TX signal to generate a further mixed TX signal.

14 . The multi-band FDD transceiver system according to claim 1 , further including:
a further LO, configured to provide a further LO signal; a further RX path mixer, configured to mix the further LO signal with a further RX signal to generate a further mixed RX signal.

15 . The multi-band FDD transceiver system according to claim 1 , further comprising:
a low-noise amplifier (LNA), configured to amplify the received RF signal prior to the RX path mixer mixing the LO signal with the received RF signal, and/or a power amplifier, configured to amplify the upconverted TX signal.

16 . A multi-band frequency division duplex (FDD) transceiver, comprising:
a first local oscillator (LO), configured to provide a first LO signal; a second LO, configured to provide a second LO signal; a first receive (RX) path mixer, configured to mix the first LO signal with a first RX signal to generate a first mixed RX signal; a second RX path mixer, configured to mix the first LO signal with a second RX signal to generate a second mixed RX signal; a first transmit (TX) path mixer, configured to mix the first LO signal with a first TX signal to generate a first mixed TX signal; and a second TX path mixer, configured to mix the second LO signal with a second TX signal to generate a second mixed TX signal.

17 . The multi-band FDD transceiver system according to claim 16 , wherein each of the first RX signal, the second RX signal, the first TX signal, and the second TX signal is in a respective different band of frequencies.

18 . The multi-band FDD transceiver system according to claim 16 , further including:
a third RX path mixer, configured to mix the first LO signal with a third RX signal to generate a third mixed RX signal; and a third TX path mixer, configured to mix the first LO signal with a third TX signal to generate a third mixed TX signal.

19 . The multi-band FDD transceiver system according to claim 18 , further including:
a fourth RX path mixer, co

Assignees

• Analog Devices International Unlimited Co

Inventors

• Montalvo Antonio
• Cobb Michael
• Guo Qi
• Jing Hao

Classifications

• H04B1/0057

  using diplexing or multiplexing filters for selecting the desired band · CPC title

• H04L5/14 Primary

  Two-way operation using the same type of signal, i.e. duplex · CPC title

• H03B5/12 Primary

  active element in amplifier being semiconductor device (H03B5/14 takes precedence) · CPC title

• H04B1/005

  adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges · CPC title