MIXER WITH HIGH OUTPUT POWER ACCURACY AND LOW LOCAL OSCILLATOR LEAKAGE
First Claim
1. A circuit comprising:
- a plurality of mixer and frequency divider pairs (MFDP), wherein each MFDP can be enabled and disabled separately of each other MFDP, wherein the frequency divider of each MFDP supplies a local oscillator signal to the mixer of the MFDP if the MFDP is enabled, wherein the frequency divider of each MFDP does not supply a local oscillator signal to the mixer of the MFDP if the MFDP is disabled, wherein each MFDP has an output lead, and wherein the output leads of all the MFDPs are coupled together; and
a frequency synthesizer adapted to supply a drive signal to the frequency divider of each of the MFDPs.
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Abstract
A circuit receives a first signal (for example, a baseband signal) and mixes it with a local oscillator (LO) signal, and outputs a second signal (for example, an RFOUT signal). The circuit includes multiple identical Mixer and Frequency Divider Pair (MFDP) circuits. Each MFDP can be enabled separately. Each MFDP includes a mixer and a frequency divider that provides the mixer with a local version of the LO signal. The MFDP outputs are coupled together so that the output power of the second signal (RFOUT) is the combined output powers of the various MFDPs. By controlling the number of enabled MFDPs, the output power of the second signal is controlled. Because the MFDPs all have identical layouts, accuracy of output power step size is improved. Because LO signal power within the circuit automatically changes in proportion to the number of enabled MFDPs, local oscillator leakage problems are avoided.
53 Citations
22 Claims
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1. A circuit comprising:
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a plurality of mixer and frequency divider pairs (MFDP), wherein each MFDP can be enabled and disabled separately of each other MFDP, wherein the frequency divider of each MFDP supplies a local oscillator signal to the mixer of the MFDP if the MFDP is enabled, wherein the frequency divider of each MFDP does not supply a local oscillator signal to the mixer of the MFDP if the MFDP is disabled, wherein each MFDP has an output lead, and wherein the output leads of all the MFDPs are coupled together; and a frequency synthesizer adapted to supply a drive signal to the frequency divider of each of the MFDPs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A circuit comprising:
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a frequency synthesizer that outputs a drive signal; a first frequency divider that receives the drive signal from the frequency synthesizer, the first frequency divider outputting a first local oscillator signal if the first frequency divider is enabled; a first mixer coupled to receive the first local oscillator signal from the first frequency divider, wherein if the first frequency divider is enabled then the first mixer is enabled and if the first frequency divider is disabled then the first mixer is disabled; a second frequency divider that receives the drive signal from the frequency synthesizer, the second frequency divider outputting a second local oscillator signal if the second frequency divider is enabled; a second mixer coupled to receive the second local oscillator signal from the second frequency divider, wherein if the second frequency divider is enabled then the second mixer is enabled and if the second frequency divider is disabled then the second mixer is disabled; a third frequency divider that receives the drive signal from the frequency synthesizer, the third frequency divider outputting a third local oscillator signal if the third frequency divider is enabled; a third mixer coupled to receive the third local oscillator signal from the third frequency divider, wherein if the third frequency divider is enabled then the third mixer is enabled and if the third frequency divider is disabled then the third mixer is disabled; and a driver amplifier, wherein the first, second and third mixers together supply an input signal to the driver amplifier, and wherein the first, second and third mixers can be enabled and disabled independently of one another to change a power with which the input signal drives the driver amplifier. - View Dependent Claims (11, 12, 13)
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14. A method comprising:
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driving an input of an amplifier using one or more of a plurality of mixer and frequency divider pairs (MFDPs), wherein each MFDP has a substantially identical layout, and wherein each MFDP can be enabled or disabled independently of an enabling or disabling of the other MFDPs; using a frequency synthesizer to supply a drive signal onto an input of the frequency divider of each of the MFDPs; and changing the number of the MFPDs that are enabled and thereby changing a power with which the plurality of MFDPs drives the input of the amplifier. - View Dependent Claims (15, 16, 17)
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18. A radio transmitter circuit comprising:
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a baseband filter; an amplifier taken from the group consisting of;
a driver amplifier, and a power amplifier; andmeans for receiving a baseband signal from the baseband filter and for driving the amplifier, wherein the means can be controlled to change an output power with which the means drives the amplifier, wherein a local oscillator leakage signal at the input of the amplifier has a power, and wherein the ratio of the output power to the power of the local oscillator leakage signal is substantially constant as the output power changes. - View Dependent Claims (19, 20, 21, 22)
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Specification