Semiconductor device and receiver
AssigneeFujitsu Limited
InventorKazuhiro Tomita
Life of this patent
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Abstract
A semiconductor device for demodulating a received signal in a satisfactory manner when the frequency of the received signal deviates. The semiconductor device is used in a receiver having a reference oscillator. The semiconductor device includes a local oscillator, a PLL controller, and a comparator. The local oscillator generates a local signal having a local frequency. The PLL controller controls the local frequency in accordance with a reference signal of the reference oscillator. The comparator compares the frequency of the received signal with the frequency of the reference signal or the phase of the received signal with the phase of the reference signal to generate an error signal for correcting the local frequency in accordance with the comparison.
Claims18
A semiconductor device for a receiver having a reference oscillator and a band pass filter, wherein the receiver uses a reference signal generated by the reference oscillator to receive a signal in a predetermined channel bandwidth, the semiconductor device comprising:
- a local oscillator for generating a local signal having a local frequency;
- a PLL controller connected to the local oscillator for controlling the local frequency in accordance with the reference signal to set the channel bandwidth;
- a comparator connected to the local oscillator for comparing frequency of the received signal with frequency of the reference signal or phase of the received signal with phase of the reference signal and generating an error signal in accordance with the comparison to correct the local frequency;
- and
- a frequency controller connected to the band pass filter to set a center frequency of the band pass filter using the reference signal.
A semiconductor device for a receiver having a reference oscillator and a band pass filter, wherein the receiver uses a reference signal generated by the reference oscillator to receive a signal in a predetermined channel bandwidth, the semiconductor device comprising:
- a local oscillator for generating a local signal;
- a first control loop including the local oscillator for controlling a frequency of the local signal based on the reference signal to set the channel bandwidth;
- a second control loop including the local oscillator for comparing frequency of the received signal with frequency of the reference signal or phase of the received signal with phase of the reference signal and generating an error signal in accordance with the comparison to correct the local frequency;
- and
- a frequency controller connected to the band pass filter to set a center frequency of the band pass filter using the reference signal.
A semiconductor device for a receiver having a reference oscillator and a band pass filter, wherein the receiver uses a reference signal generated by the reference oscillator to receive a signal of a predetermined channel, the semiconductor device comprising:
- a local oscillator for generating a local signal;
- a mixer connected to the local oscillator for generating an intermediate frequency signal having a predetermined intermediate frequency with the local signal and the received signal;
- a PLL controller connected to the local oscillator for setting a frequency of the local signal with the reference signal to receive the received signal of the predetermined channel;
- a comparator connected to the local oscillator for comparing a frequency of the intermediate frequency signal with frequency of the reference signal or phase of the intermediate frequency signal with phase of the reference signal and generating an error signal in accordance with the comparison to correct the frequency of the local signal;
- and
- a frequency controller connected to the band pass filter to set a center frequency of the band pass filter using the reference signal.
A receiver for receiving a signal, the receiver comprising:
- a reference oscillator for generating a reference frequency signal having a reference frequency;
- a local oscillator for generating a local signal;
- a band pass filter having a predetermined passage bandwidth;
- a channel setting circuit connected to the reference oscillator and the local oscillator for controlling frequency of the local signal in accordance with the reference frequency signal and setting the passage bandwidth of the band pass filter to a predetermined channel bandwidth;
- a frequency correction circuit for comparing frequency of the received signal received in the channel bandwidth with frequency of the reference signal or phase of the received signal with phase of the reference signal and generating an error signal in accordance with the comparison to correct the frequency of the local signal;
- and
- a frequency controller connected to the band pass filter to set a center frequency of the band pass filter using the reference signal.
A method for correcting frequency of a local signal in a receiver, wherein the receiver includes a reference oscillator for generating a reference signal having a reference frequency, and a band pass filter, the method comprising:
- setting a center frequency of the band pass filter with the reference signal;
- generating a local signal for receiving a received signal of a predetermined channel with the reference signal;
- generating an intermediate frequency signal having a predetermined intermediate frequency with the received signal and the local signal;
- providing the intermediate frequency signal to the band pass filter;
- generating an error signal in accordance with a comparison between frequency of the intermediate frequency signal that passed through the band pass filter and frequency of the reference signal or a comparison between phase of the intermediate frequency signal with phase of the reference signal;
- and
- correcting the frequency of the local signal in accordance with the error signal.
Dependencies are inferred from the claim text.