RF-to-baseband receiver architecture
First Claim
1. Radio frequency (RF) receiver circuitry configured for receiving an RF signal and down-converting said RF signal to base band, said receiver circuitry comprising:
- (a) RF-to-IF conversion circuitry configured for RF-to-IF conversion of said RF signal to an IF signal, said RF-to-IF conversion circuitry comprising mixer circuitry for down-converting said RF signal to a band pass IF signal;
local oscillator circuitry configured for injection locking and generating an RF-to-IF mixing signal for input to said mixer circuitry, said mixing signal having a frequency which is a first pre-selected harmonic of a reference frequency; and
, tunable IF filter circuitry configured for pre-tuning said IF filter to said band of said band pass IF signal and, when so tuned, for filtering said band pass IF signal;
(b) IF-to-base band conversion circuitry configured for IF-to-base band conversion of said IF signal, said IF-to-base band conversion circuitry comprising sub-sampling and down-conversion circuitry operating at a sampling frequency of a sampling signal input thereto, said sampling frequency being a second pre-selected harmonic of said reference frequency; and
, (c) reference frequency source circuitry configured for generating a reference signal of said reference frequency;
wherein each of said mixing signal and said sampling signal is derived from said reference signal as a harmonic thereof.
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Abstract
An improved receiver architecture and method for a wireless transceiver (e.g. for a headphone) is provided whereby the receiver, advantageously, enables the use of only one synthesizer circuit for both the RF-to-IF and IF-to-base band conversion processes which, in turn, provides for lower power consumption. The receiver includes an injection locked local receiver oscillator (Rx LO) which is used for the first mixing stage (i.e. the RF-to-IF conversion). The Rx LO 105 is thereby able to use a high-level harmonic of a relatively low reference frequency signal produced by that synthesizer (e.g. a fractional-N phase locked loop circuit (PLL)). The receiver further includes a tunable Q-enhanced IF filter 110 and complex sub-sampling and mixing down-conversion circuitry for the second conversion stage (i.e. IF-to-baseband conversion). The sampling frequency used for the second conversion stage is a harmonic of the reference frequency derived from the synthesizer (PLL). For example, transceiver channels may be designed on the basis that the RF frequency fRF is assigned a value of (n±¼)·fs, where the frequency fPLL of the PLL may be chosen to be twice the sub-sampling frequency fs and the frequency fRx LO of the Rx LO may be nine times the frequency fPLL.
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Citations
20 Claims
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1. Radio frequency (RF) receiver circuitry configured for receiving an RF signal and down-converting said RF signal to base band, said receiver circuitry comprising:
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(a) RF-to-IF conversion circuitry configured for RF-to-IF conversion of said RF signal to an IF signal, said RF-to-IF conversion circuitry comprising mixer circuitry for down-converting said RF signal to a band pass IF signal;
local oscillator circuitry configured for injection locking and generating an RF-to-IF mixing signal for input to said mixer circuitry, said mixing signal having a frequency which is a first pre-selected harmonic of a reference frequency; and
, tunable IF filter circuitry configured for pre-tuning said IF filter to said band of said band pass IF signal and, when so tuned, for filtering said band pass IF signal;
(b) IF-to-base band conversion circuitry configured for IF-to-base band conversion of said IF signal, said IF-to-base band conversion circuitry comprising sub-sampling and down-conversion circuitry operating at a sampling frequency of a sampling signal input thereto, said sampling frequency being a second pre-selected harmonic of said reference frequency; and
,(c) reference frequency source circuitry configured for generating a reference signal of said reference frequency;
wherein each of said mixing signal and said sampling signal is derived from said reference signal as a harmonic thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for receiving an RF signal and down-converting said RF signal to base band, said method comprising:
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(a) down-converting said RF signal to a band pass IF signal including injection locking local oscillator circuitry to generate a mixing signal for use in said RF-to-IF down-converting, said mixing signal having a frequency which is a first pre-selected harmonic of a reference frequency; and
, pre-tuning tunable IF filter circuitry to said band of said band pass IF signal and, when so tuned, filtering said band pass IF signal; and
,(b) down-converting said IF signal to a base band signal including sub-sampling said IF signal at a sampling frequency which is a second pre-selected harmonic of said reference frequency. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification