Data signal correction circuit, receiver, and data signal correction method

1. A data signal correction circuit comprising:

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value; and

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity such that the input interval set when the delay quantity is at a first level, is greater than the input interval set when the delay quantity is at a second level that is higher than the first level, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval.

2. A data signal correction circuit comprising:

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value;

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval; and

a low pass filter arranged after the adaptive filter,

wherein the low pass filter is configured to receive an output from the adaptive filter and the delay quantity as input items and vary a cutoff frequency in accordance with the delay quantity.

3. A data signal correction circuit comprising:

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value; and

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval,

wherein the adaptive filter includes a table that describes a correspondence relationship between the delay quantity and the input interval.

4. The data signal correction circuit according to claim 2 , wherein the low pass filter includes a table that describes a correspondence relationship between the delay quantity and the cutoff frequency.

5. A data signal correction circuit comprising:

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value; and

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval,

wherein the adaptive filter does not vary the input interval when the delay quantity is at or above a third level, and wherein the adaptive filter inputs the channel characteristic estimate value every K carriers (where K is an integer equal to or greater than 2) when the delay quantity is below the third level.

6. The data signal correction circuit according to claim 2 , wherein the low pass filter does not perform frequency cutoff when the delay quantity is at or above a fourth level, and wherein the low pass filter performs frequency cutoff at the selected cutoff frequency in accordance with the delay quantity when the delay quantity is below the fourth level.

7. A receiver comprising:

a signal receiver unit;

a data signal correction circuit configured to perform channel correction on a data signal received at the signal receiver unit, the data signal correction circuit including

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal,

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value, and

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity such that the input interval set when the delay quantity is at a first level, is greater than the input interval set when the delay quantity is at a second level that is higher than the first level, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval; and

a modulator and decoder unit configured to modulate and decode the channel-corrected data signal to output at least one of a video signal and an audio signal.

8. A receiver comprising:

a signal receiver unit;

a data signal correction circuit configured to perform channel correction on a data signal received at the signal receiver unit, the data signal correction circuit including

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal,

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value, and

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval; and

a modulator and decoder unit configured to modulate and decode the channel-corrected data signal to output at least one of a video signal and an audio signal,

wherein the data signal correction circuit further includes a low pass filter arranged after the adaptive filter, and wherein the low pass filter is configured to receive an output from the adaptive filter and the delay quantity as input items and vary a cutoff frequency in accordance with the delay quantity.

9. A receiver comprising:

a signal receiver unit;

a data signal correction circuit configured to perform channel correction on a data signal received at the signal receiver unit, the data signal correction circuit including

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal,

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value, and

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval; and

a modulator and decoder unit configured to modulate and decode the channel-corrected data signal to output at least one of a video signal and an audio signal,

wherein the adaptive filter includes a table that describes a correspondence relationship between the delay quantity and the input interval.

10. The receiver according to claim 8 , wherein the low pass filter includes a table that describes a correspondence relationship between the delay quantity and the cutoff frequency.

11. A receiver comprising:

a signal receiver unit;

a data signal correction circuit configured to perform channel correction on a data signal received at the signal receiver unit, the data signal correction circuit including

a channel characteristic calculator unit configured to calculate a channel characteristic estimate value of a received data signal on the basis of a pilot signal,

a path detector unit configured to determine a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value, and

an adaptive filter configured to receive the delay quantity and the channel characteristic estimate value as input items, adjust an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity, and perform adaptive equalization on the channel characteristic estimate value inputted to the adaptive filter at the adjusted input interval; and

a modulator and decoder unit configured to modulate and decode the channel-corrected data signal to output at least one of a video signal and an audio signal,

wherein the adaptive filter does not vary the input interval when the delay quantity is at or above a third level, and wherein the adaptive filter inputs the channel characteristic estimate value every K carriers (where K is an integer equal to or greater than 2) when the delay quantity is below the third level.

12. The receiver according to claim 8 , wherein the low pass filter does not perform frequency cutoff when the delay quantity is at or above a fourth level, and wherein the low pass filter performs frequency cutoff at the selected cutoff frequency in accordance with the delay quantity when the delay quantity is below the fourth level.

13. A data signal correction method comprising:

calculating, at a receiver, a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

determining a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value; and

performing adaptive equalization on the calculated channel characteristic estimate value by adjusting an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity such that the input interval set when the delay quantity is at a first level, is greater than the input interval set when the delay quantity is at a second level that is higher than the first level.

14. A data signal correction method comprising:

calculating, at a receiver, a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

determining a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value;

performing adaptive equalization on the calculated channel characteristic estimate value by adjusting an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity;

selecting a cutoff frequency in accordance with the delay quantity; and

filtering the adaptively-equalized channel characteristic estimate value at the selected cutoff frequency.

15. A data signal correction method comprising:

calculating, at a receiver, a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

determining a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value;

performing adaptive equalization on the calculated channel characteristic estimate value by adjusting an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity; and

storing a correspondence relationship between the delay quantity and the input interval in a memory prior to the performing adaptive equalization.

16. The data signal correction method according to claim 14 , further comprising:

storing a correspondence relationship between the delay quantity and the cutoff frequency in a memory prior to the performing adaptive equalization.

17. A data signal correction method comprising:

calculating, at a receiver, a channel characteristic estimate value of a received data signal on the basis of a pilot signal;

determining a delay quantity of multipath propagation of the received data signal on the basis of the calculated channel characteristic estimate value; and

performing adaptive equalization on the calculated channel characteristic estimate value by adjusting an input interval of the channel characteristic estimate value along a carrier frequency axis in accordance with the delay quantity,

wherein the input interval is not varied when the delay quantity is at or above a third level, and wherein the channel characteristic estimate value is varied every K carriers (where K is an integer equal to or greater than 2) when the delay quantity is below the third level.

18. The data signal correction method according to claim 14 , wherein frequency cutoff is not performed for the filtering when the delay quantity is at or above a fourth level, and wherein frequency cut off is performed at the selected cutoff frequency in accordance with the delay quantity when the delay quantity is below the fourth level.