SAW-LESS RECEIVER WITH A FREQUENCY TRANSLATED BPF HAVING A NEGATIVE RESISTANCE
A SAW-less receiver includes an FEM interface module, an RF to IF receiver section, and a receiver IF to baseband section. The RF to IF receiver section includes an RF frequency translated bandpass filter (FTBPF), an LNA, and a mixing section. The RF FTBPF frequency translates a baseband filter response to an RF filter response and filters an inbound RF signal in accordance with the RF filter response, wherein the inbound RF signal includes a loss error due to switching loss and/or inductor loss. The RF FTBPF also compensates the loss error based on a negative resistance. The LNA amplifies the compensated inbound RF signal and the mixing section mixes the amplified inbound RF signal with a local oscillation to produce an inbound IF signal. The receiver IF to baseband section converts the inbound IF signal into one or more inbound symbol streams.
1 . A surface acoustic wave (SAW)-less receiver comprises:
a front end module (FEM) interface module operable to receive an inbound radio frequency (RF) signal that includes a loss error due to at least one of switching loss and inductor loss;
a radio frequency (RF) to intermediate frequency (IF) receiver section including:
an RF frequency translated bandpass filter (FTBPF) operable to:
frequency translate a baseband filter response to an RF filter response;
filter the inbound RF signal in accordance with the RF filter response to produce a filtered inbound RF signal; and
compensate the loss error of the filtered inbound RF signal based on a negative resistance to produce a compensated inbound RF signal;
a low noise amplifier module operable to amplify the compensated inbound RF signal to produce an amplified inbound RF signal;
a mixing section operable to mix the amplified inbound RF signal with a local oscillation to produce an inbound IF signal; and
a receiver IF to baseband section operable to convert the inbound IF signal into one or more inbound symbol streams.
2 . The SAW-less receiver of claim 1 , wherein the low noise amplifier (LNA) module further comprises:
an LNA frequency translated bandpass filter (FTBPF) operable to:
frequency translate a second baseband filter response to a second RF filter response; and
filter the compensated inbound RF signal in accordance with the second RF filter response to produce a second filtered inbound RF signal; and
a low noise amplifier operable to amplify the second filtered inbound RF signal to produce the amplified inbound RF signal.
3 . The SAW-less receiver of claim 1 , wherein the FTBPF is further operable to:
receive a control signal; and
adjust the negative resistance in accordance with the control signal.
4 . The SAW-less receiver of claim 1 , wherein the FTBPF is further operable to filter the inbound RF signal by:
attenuating at least one of an image signal component and an undesired signal component of the inbound RF signal; and
passing, substantially unattenuated, a desired signal component of the inbound RF signal as the filtered inbound RF signal.
5 . The SAW-less receiver of claim 1 , wherein the FEM interface module comprises:
a transformer; and
a tunable capacitor network Cl operably coupled to a secondary of the transformer and to filter a received inbound RF signal to produce the inbound RF signal.
6 . The SAW-less receiver of claim 1 further comprises:
a front end module operable to isolate the inbound RF signal from an undesired RF signal.
7 . The SAW-less receiver of claim 1 , wherein the receiver IF to BB section comprises:
a mixing section operable to mix the inbound IF signal with a second local oscillation to produce I and Q mixed signals; and
a combining & filtering section operable to:
combine the I and Q mixed signals to produce a combined signal; and
filter the combined signal to produce the one or more inbound symbol streams.
8 . The SAW-less receiver of claim 1 , wherein the mixing section comprises:
a mixing module operable to:
convert the amplified inbound RF signal into an in-phase (I) signal component and a quadrature (Q) signal component;
mix the I signal component with an I signal component of a local oscillation to produce an I mixed signal;
mix the Q signal component with a Q signal component of the local oscillation to produce a Q mixed signal; and
a filter module operable to filter the I and Q mixed signals to produce the inbound IF signal.
9 . The SAW-less receiver of claim 1 , wherein the FTBPF comprises:
a switching network;
a first set of baseband impedances;
a second set of baseband impedances, wherein the first and second sets of baseband impedances form the baseband frequency response and wherein the switching network is operable to couple the first and second sets of baseband impedances to the FEM interface module in accordance with a plurality of phase offset clock signals having a clock rate corresponding to a frequency of the inbound RF signal;
a first negative resistance module operably coupled to the first set of baseband impedances; and
a second negative resistance module operably coupled to the second set of baseband impedances.
10 . The SAW-less receiver of claim 9 further comprises:
in accordance with a first clock signal of the plurality of phase offset clock signals, the switching network couples a first one of the first set of baseband impedances to the FEM interface module;
in accordance with a second clock signal of the plurality of phase offset clock signals, the switching network couples a first one of the second set of baseband impedances to the FEM interface module;
in accordance with a third clock signal of the plurality of phase offset clock signals, the switching network couples a second one of the first set of baseband impedances to the FEM interface module; and
in accordance with a fourth clock signal of the plurality of phase offset clock signals, the switching network couples a second one of the second set of baseband impedances to the FEM interface module.
11 . A radio frequency (RF) to intermediate frequency (IF) receiver section comprises:
an RF frequency translated bandpass filter (FTBPF) operable to:
frequency translate a baseband filter response to an RF filter response;
filter an inbound RF signal in accordance with the RF filter response to produce a filtered inbound RF signal; and
compensate a loss error of the filtered inbound RF signal based on a negative resistance to produce a compensated inbound RF signal;
a low noise amplifier module operable to amplify the compensated inbound RF signal to produce an amplified inbound RF signal; and
a mixing section operable to mix the amplified inbound RF signal with a local oscillation to produce an inbound IF signal.
12 . The RF to IF receiver section of claim 11 , wherein the low noise amplifier (LNA) module further comprises:
an LNA frequency translated bandpass filter (FTBPF) operable to:
frequency translate a second baseband filter response to a second RF filter response; and
filter the compensated inbound RF signal in accordance with the second RF filter response to produce a second filtered inbound RF signal; and
a low noise amplifier operable to amplify the second filtered inbound RF signal to produce the amplified inbound RF signal.
13 . The RF to IF receiver section of claim 11 , wherein the FTBPF is further operable to:
receive a control signal; and
adjust the negative resistance in accordance with the control signal.
14 . The RF to IF receiver section of claim 11 , wherein the FTBPF is further operable to filter the inbound RF signal by:
attenuating at least one of an image signal component and an undesired signal component of the inbound RF signal; and
passing, substantially unattenuated, a desired signal component of the inbound RF signal as the filtered inbound RF signal.
15 . The RF to IF receiver section of claim 11 , wherein the mixing section comprises:
a mixing module operable to:
convert the amplified inbound RF signal into an in-phase (I) signal component and a quadrature (Q) signal component;
mix the I signal component with an I signal component of a local oscillation to produce an I mixed signal;
mix the Q signal component with a Q signal component of the local oscillation to produce a Q mixed signal; and
a filter module operable to filter the I and Q mixed signals to produce the inbound IF signal.
16 . The RF to IF receiver section of claim 11 , wherein the FTBPF comprises:
a switching network;
a first set of baseband impedances;
a second set of baseband impedances, wherein the first and second sets of baseband impedances form the baseband frequency response and wherein the switching network is operable to couple the first and second sets of baseband impedances to the FEM interface module in accordance with a plurality of phase offset clock signals having a clock rate corresponding to a frequency of the inbound RF signal;
a first negative resistance module operably coupled to the first set of baseband impedances; and
a second negative resistance module operably coupled to the second set of baseband impedances.
17 . The RF to IF receiver section of claim 16 further comprises:
in accordance with a first clock signal of the plurality of phase offset clock signals, the switching network couples a first one of the first set of baseband impedances to the FEM interface module;
in accordance with a second clock signal of the plurality of phase offset clock signals, the switching network couples a first one of the second set of baseband impedances to the FEM interface module;
in accordance with a third clock signal of the plurality of phase offset clock signals, the switching network couples a second one of the first set of baseband impedances to the FEM interface module; and
in accordance with a fourth clock signal of the plurality of phase offset clock signals, the switching network couples a second one of the second set of baseband impedances to the FEM interface module.