Local oscillation signal supply method and circuit therefor

• US 7,187,723 B1
• Filed: 09/22/2000
• Issued: 03/06/2007
• Est. Priority Date: 09/24/1999
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kawanabe, Yoshitaka
• Primary Examiner(s): Fan; Chieh M.
• Assistant Examiner(s): PUENTE, EVA YI ZHENG
• Application Number:
  US10/088,689
• Time in Patent Office: 2,356 Days
• Field of Search: 375/342, 375/134, 375/316, 342/372, 342/371, 342/382, 455/182
• US Class Current: 375/316
• CPC Class Codes: H04B 1/14 Automatic detuning arrangements
• CPC Class Codes: H04B 15/06 by local oscillators of receivers
• CPC Class Codes: H04B 7/084 Equal gain combining, only phase adjustments antenna beam scanning or forming by phase or amplitude control H01Q3/26, e.g. phased arrays
• CPC Class Codes: H04B 7/0894 using different delays between antennas
• CPC Class Codes: H04L 2027/0016 Stabilisation of local oscillators

Abstract

With the object of accurately reproducing, by means of a small-scale circuit, differences in propagation delay at antennas of received signals that are received as input by way of each of a plurality of receivers, frequency data generator 6 supplies frequency data that contain a frequency component that is synchronized in common to the plurality of receivers 2-1 to 2-n. At receiver 2-n, local oscillation signal generator 3-n, which is represented by a D/A converter, generates a local oscillation signal from frequency data that have been synchronized in common. The passing phase of a received signal that is outputted from antenna 1-n by way of receiver 1-n is thus fixed, and as a result, the phase difference of received signals that are received by DSP 8 by way of the plurality of receivers 2-1 to 2-n becomes the propagation delay difference of the received signals. As frequency data, frequency data that contain a plurality of frequency components are supplied to each receiver 2-n, and the frequency data are selected inside receiver 2-n and subjected to quadrature modulation to enable generation of local oscillation signals of differing intermediate frequencies.

Claims

1. A local oscillation signal supply method that is used when received signals, which are received as input by way of a plurality of receivers that are each connected to respective antennas, are demodulated and outputted by a digital signal processor, the method comprising:

generating frequency data that contain a frequency component;

sending said frequency data as a common signal source to each of said plurality of receivers via signal sequences that correspond to a wireless channel, the signal source supplied as a digital signal;

in each of said receivers, converting the digital signal to an analog signal based on a clock signal that is common to all of said receivers; and

in each of said receivers, generating local oscillation signals in which phase and amplitude are matched in all of said receivers based on said analog signal, wherein the frequency data that are received from the plurality of said signal sequences are each subjected to quadrature amplitude modulation to generate respective of the local oscillation signals having a prescribed frequency.

2. A local oscillation signal supply method that is used when received signals, which are received as input by way of a plurality of receivers that are each connected to respective antennas, are demodulated and outputted by a digital signal processor, the method comprising:

generating frequency data that contain a frequency component;

sending said frequency data as a common signal source to each of said plurality of receivers via signal sequences that correspond to a wireless channel, the signal source supplied as a digital signal;

providing a plurality of said signal sequences supplying shift data, which correspond to phase advance data for said frequency data, to all of said receivers;

in each of said receivers, converting the digital signal to an analog signal based on a clock signal that is common to all of said receivers;

in each of said receivers, generating local oscillation signals in which phase and amplitude are matched in all of said receivers based on said analog signal, wherein, in each of said receivers, shift data, in which a prescribed frequency is obtained from each of said plurality of signal sequences, are selected and subjected to signal conversion, and shift data that have undergone selection and conversion and said frequency data are subjected to quadrature modulation to generate respective of the local oscillation signals having a prescribed frequency.

3. A local oscillation signal supply circuit that is used when received signals, which are received as input by a plurality of receivers that are each connected to respective antennas, are demodulated and outputted by a digital signal processor, said local oscillation signal supply circuit comprising:

a single frequency data generator that generates frequency data that contain a frequency component and sends these data as a common signal source as digital signals to each of said plurality of receivers by way of a single signal sequence that corresponds to a wireless channel; and

a local oscillation signal generator at each of the receivers including;

a digital/analog converter that converts said digital signals to analog signals based on a clock signal that is common to all of said receivers; and

a quadrature modulator that performs quadrature modulation of said analog signals to generate a local oscillation signal having a prescribed frequency, in which phase and amplitude are matched at all of said receivers based on said analog signals.

4. A local oscillation signal supply circuit that is used when received signals, which are received as input by a plurality of receivers that are each connected to respective antennas, are demodulated and outputted by a digital signal processor, said local oscillation signal supply circuit comprising:

a single frequency data generator that generates frequency data that contain a frequency component and sends these data as a common signal source as digital signals to each of said plurality of receivers by way of a single signal sequence that corresponds to a wireless channel;

a shift data generator that provides a plurality of signal sequences for outputting shift data corresponding to phase advance data for said frequency data, to all of said receivers; and

a local oscillation signal generator at each of the receivers including;

a digital/analog converter that converts said digital signals to analog signals based on a clock signal that is common to all of said receivers;

a selector/converter that selects from the shift data and signal-converts the selected shift data, from which a desired frequency is obtained from the plurality of said signal sequences; and

a quadrature modulator that performs quadrature modulation of shift data that have undergone selection and conversion and said analog signal to generate a local oscillation signal having a desired frequency, in which phase and amplitude are matched at all of said receivers based on said analog signals.