Apparatus and method for operating a phase locked loop frequency synthesizer responsive to radio frequency channel spacing
First Claim
1. In a radio frequency transceiver operating in a radio frequency band including a plurality of radio frequency channels, wherein channel spacing is defined as a difference in frequency between two adjacent channels of the radio frequency band, wherein the channel spacing varies over the radio frequency band, wherein the radio frequency transceiver includes a phase locked loop (PLL) frequency synthesizer operative to tune the radio frequency transceiver to a radio frequency channel in the radio frequency band and operative to generate an output frequency signal, wherein the PLL frequency synthesizer has an adjustable loop bandwidth, a method for operating the PLL frequency synthesizer comprising the steps of:
- determining the channel spacing of the radio frequency channels in a portion of the radio frequency band including the radio frequency channel; and
adjusting the loop bandwidth of the PLL frequency synthesizer responsive to the determined channel spacing.
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Abstract
An apparatus and method for operating a phase locked loop frequency synthesizer responsive to radio frequency channel spacing. The phase locked loop (PLL) frequency synthesizer (300) tunes a radio frequency transceiver (100) to a radio frequency channel. A processor (110) in the transceiver (100) determines the channel spacing of the radio frequency channels in a portion of a radio frequency band including the radio frequency channel, and controls the PLL frequency synthesizer (300) responsive to the determined channel spacing. The present invention advantageously provides the PLL frequency synthesizer (300) with faster lock time and lower noise.
32 Citations
6 Claims
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1. In a radio frequency transceiver operating in a radio frequency band including a plurality of radio frequency channels, wherein channel spacing is defined as a difference in frequency between two adjacent channels of the radio frequency band, wherein the channel spacing varies over the radio frequency band, wherein the radio frequency transceiver includes a phase locked loop (PLL) frequency synthesizer operative to tune the radio frequency transceiver to a radio frequency channel in the radio frequency band and operative to generate an output frequency signal, wherein the PLL frequency synthesizer has an adjustable loop bandwidth, a method for operating the PLL frequency synthesizer comprising the steps of:
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determining the channel spacing of the radio frequency channels in a portion of the radio frequency band including the radio frequency channel; and adjusting the loop bandwidth of the PLL frequency synthesizer responsive to the determined channel spacing. - View Dependent Claims (2, 3, 4, 5)
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6. In a radio frequency transceiver operating in a radio frequency band including a plurality of radio frequency channels, wherein channel spacing is defined as a difference in frequency between two adjacent channels of the radio frequency band, wherein the channel spacing varies over the radio frequency band, wherein the radio frequency transceiver includes a phase locked loop (PLL) frequency synthesizer operative to tune the radio frequency transceiver to a radio frequency channel in the radio frequency band and operative to generate an output frequency signal, wherein the PLL frequency synthesizer has an adjustable loop bandwidth, an apparatus for operating the PLL frequency synthesizer comprising:
a processor operative to determine the channel spacing of the radio frequency channels in a portion of the radio frequency band including the radio frequency channel; and
operative to adjust the loop bandwidth of the PLL frequency synthesizer responsive to the determined channel spacing.
Specification