Multi-tap, digital-pulse-driven mixer
AssigneeTexas Instruments Incorporated
InventorsRobert B. Staszewski, Dirk Leipold
Life of this patent
Estimating the term…
Abstract
A multi-tap, digital-pulse-driven mixer advantageously avoids local oscillator (11) leakage by shifting the local oscillator frequency (FLO) out of the received frequency band. Low noise figures are advantageously realized by the use of digital pulses (51, 52) as mixer drive signals (16).
Claims28
A method of downconverting a first communication signal at a first frequency into a second communication signal at a second frequency that is lower than the first frequency, comprising:
- providing an oscillator signal having a third frequency that is lower than the first frequency;
- producing in response to the oscillator signal a sampling pulse signal having digital pulses for use in sampling the first communication signal, wherein adjacent pulses of the sampling pulse signal are separated by an amount of time that corresponds to a predetermined number of cycles of the first communication signal and wherein said amount of time is greater than an amount of time required for completion of said predetermined number of cycles of the first communication signal;
- using the pulses of the sampling pulse signal to sample selected phases of the first communication signal, including using a first pulse of the sampling pulse signal to sample a first chase of a first cycle of the first communication signal and using a second pulse of the sampling pulse signal to sample a second phase of a second cycle of the first communication signal in which said first and second pulses are adjacent one another in the sampling pulse signal, wherein said second phase is a different phase than said first phase, and wherein said second cycle follows said first cycle by a number of cycles of the first communication signal equal to said predetermined number;
- and
- using the sampled phases to produce the second communication signal.
A method of downconverting a first communication signal at a first frequency into a second communication signal at a second frequency that is lower than the first frequency, comprising:
- sampling a plurality of phases of each of at least two consecutive cycles of the first communication signal, wherein said sampling step includes normally activating a plurality of sampling switches in a first temporal order to sample said plurality of phases, and providing said filter function by activating said plurality of switches in a second temporal order that differs from said first temporal order;
- and
- combining the sampled phases to provide a filter function and produce the second communication signal.
An apparatus for downconverting a first communication signal at a first frequency into a second communication signal at a second frequency that is lower than the first frequency, comprising:
- an oscillator for generating a signal having a third frequency that is lower than the first frequency;
- circuitry for producing in response to the oscillator signal a sampling pulse signal having digital pulses for use in sampling the first communication signal, wherein adjacent pulses of the sampling pulse signal are separated by an amount of time that corresponds to a predetermined number of cycles of the first communication signal and wherein said amount of time is greater than an amount of time required for completion of said predetermined number of cycles of the first communication signal;
- circuitry for using the pulses of the sampling pulse signal to sample selected phases of the first communication signal, including using a first pulse of the sampling pulse signal to sample a first phase of a first cycle of the first communication signal and using a second pulse of the sampling pulse signal to sample a second phase of a second cycle of the first communication signal in which said first and second pulses are adjacent one another in the sampling pulse signal, wherein said second phase is a different phase than said first phase, and wherein said second cycle follows said first cycle by a number of cycles of the first communication signal equal to said predetermined number;
- and
- circuitry for using the sampled phases to produce the second communication signal.
An apparatus for downconverting a first communication signal at a first frequency into a second communication signal at a second frequency that is lower than the first frequency, comprising:
- circuitry for sampling a plurality of phases of each of at least two consecutive cycles of the first communication signal, wherein said sampling includes normally activating a plurality of sampling switches in a first temporal order to sample said plurality of phases, and providing a filter function by activating a plurality of switches in a second temporal order that differs from said first temporal order;
- and
- circuitry for combining the sampled phases to provide said filter function and produce the second communication signal.
Dependencies are inferred from the claim text.