Personal communications device with ratio counter
AssigneeSiRF Technology, Inc.
InventorPaul A. Underbrink
Life of this patent
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Abstract
The invention is directed to a personal communications device with a ratio counter providing tracking transitioning edges of two clocks so as to generate a signal to initiate capture of a clock cycle count. Provisions for tracking the transitioning edges include a storage memory for storing a first and a second value selected in accordance with the principles of convergents of continued fractions. A first and second counter each responding to first and second clock signal, respectively. The first and second counter each count clock cycles of the respective clock signal. A first register for capturing the count of the first counter and a second register for capturing the count of the second counter.
Claims26
A personal communications device comprising:
- first receiver comprising a first clock for generating a first clock signal;
- second receiver comprising a second clock for generating a second clock signal
- at least one register for storing first and second values;
- and
- frequency ratio counter that receives one of the first and second values in response to the first clock signal and generates a control signal under control of the received value, counts pulses of the first clock signal and the second clock signal and captures the count of each clock signal in response to the control signal, and determines a ratio between a frequency of the first clock signal and a frequency of the second clock signal using the count.
A method of determining a ratio between two clock frequencies comprising:
- reading one of a first value and a second value in response to a first clock signal and generating a control signal under control of the read value;
- counting successive clock pulses of the first clock signal for a duration of time determined in accordance with the control signal;
- counting successive clock pulses of a second clock signal for the duration of time;
- reading the count of the clock pulses of each of the first clock signal and the second clock signal upon the elapse of the duration;
- and
- determining the ratio between a frequency of the first clock signal and a frequency of the second clock signal using the count.
A personal communications device having provisions for ratio counting comprising:
- a first memory area for storing a first value;
- a second memory area for storing a second value;
- control signal generator for receiving one of the first and second values in response to a first clock signal and for outputting a control signal;
- and
- count capture unit for receiving the first clock signal and a second clock signal and counting the pulses of the first clock signal and the second clock signal and capturing the count of each clock signal in response to the control signal.
A communication device comprising:
- first means for receiving a radio frequency signal that includes a first means for generating a first clock signal;
- second means for receiving a radio frequency signal that includes a second means for generating a second clock signal;
- means for storing first and second values representative of the first and second clock signals;
- and
- means for receiving one of the first and second values in response to the first clock signal and generating a control signal under control of the received value, counting pulses of the first and second clock signals and capturing the count of each clock signal in response to the control signal, and determining a ratio between the frequency of the first clock signal and the frequency of the second clock signal using the count.
A communications device comprising:
- a first receiver that includes a first clock generating a first clock signal;
- a second receiver that includes a second clock generating a second clock signal;
- memory that stores values representative of the first and second clock signals;
- and
- a ratio counter that generates a control signal in accordance with one of the values, counts pulses of the first clock signal and the second clock signal and captures the count of each clock signal in response to the control signal, and determines a ratio between frequencies of the first and second clock signals using the count.
Dependencies are inferred from the claim text.