RECEIVER AND RECEIVING SYSTEM USING THE SAME
If receiving circuit is in a high-sensitivity mode, receiving circuit is switched to a low-sensitivity mode when the BER according to BER measurement circuit becomes more favorable than a release threshold. If receiving circuit is in the low-sensitivity mode, receiving circuit is switched to the high-sensitivity mode when the BER according to BER measurement circuit becomes more adverse than a start-up threshold. If switching between the high-sensitivity and low-sensitivity modes occurs, control is exercised so that switching from the high-sensitivity mode to the low is resistant to occurring, thereby suppressing the occurrence of a reception error caused by switching between the receiving modes.
1 .- 25 . (canceled)
26 . A receiving apparatus comprising:
a receiving circuit having a high-sensitivity mode and a low-sensitivity mode with sensitivity lower than the high-sensitivity mode;
a reception quality judging circuit judging reception quality of a reception signal output from the receiving circuit; and
a control circuit controlling switching between the high-sensitivity mode and the low-sensitivity mode according to a signal from the reception quality judging circuit,
wherein,
if the receiving circuit is in the high-sensitivity mode, the control circuit switches the receiving circuit to the low-sensitivity mode when a judgement result according to the reception quality judging circuit becomes more favorable than a release threshold; and
if the receiving circuit is in the low-sensitivity mode, the control circuit switches the receiving circuit to the high-sensitivity mode when a judgement result according to the reception quality judging circuit becomes more adverse than a start-up threshold, and
wherein, if switching between the high-sensitivity mode and the low-sensitivity mode occurs, the control circuit exercises control so that switching from the high-sensitivity mode to the low-sensitivity mode is difficult.
27 . The receiving apparatus of claim 26 , wherein, if switching between the high-sensitivity mode and the low-sensitivity mode occurs, the control circuit exercises control so that switching from the high-sensitivity mode to the low-sensitivity mode is difficult by making the release threshold more favorable.
28 . The receiving apparatus of claim 27 , wherein the control circuit returns the release threshold to an initial value if a state in which a judgement result according to the reception quality judging circuit is more favorable than the release threshold continues for a given time.
29 . The receiving apparatus of claim 26 ,
wherein the control circuit switches the receiving circuit from the high-sensitivity mode to the low-sensitivity mode if a state in which a judgement result according to the reception quality judging circuit is more favorable than the release threshold continues for a given time, and
wherein the control circuit exercises control so that switching from the high-sensitivity mode to the low-sensitivity mode is difficult by further increasing the given time if switching between the high-sensitivity mode and the low-sensitivity mode occurs.
30 . The receiving apparatus of claim 26 ,
wherein the receiving unit includes a first receiving circuit, a second receiving circuit, and a selecting or combining unit connected to an output side of the first receiving circuit and an output side of the second receiving circuit;
wherein the high-sensitivity mode is a mode in which the selecting or combining circuit performs reception using the first receiving circuit and the second receiving circuit; and
wherein the low-sensitivity mode is a mode in which the selecting or combining circuit performs reception using either one of the first receiving circuit and the second receiving circuit.
31 . The receiving apparatus of claim 27 ,
wherein the receiving unit includes a first receiving circuit, a second receiving circuit, and a selecting or combining unit connected to an output side of the first receiving circuit and an output side of the second receiving circuit;
wherein the high-sensitivity mode is a mode in which the selecting or combining unit performs reception using the first receiving circuit and the second receiving circuit; and
wherein the low-sensitivity mode is a mode in which the selecting or combining unit performs reception using either one of the first receiving circuit and the second receiving circuit.
32 . The receiving apparatus of claim 28 ,
wherein the receiving unit includes a first receiving circuit, a second receiving circuit, and a selecting or combining unit connected to an output side of the first receiving circuit and an output side of the second receiving circuit;
wherein the high-sensitivity mode is a mode in which the selecting or combining unit performs reception using the first receiving circuit and the second receiving circuit; and
wherein the low-sensitivity mode is a mode in which the selecting or combining unit performs reception using either one of the first receiving circuit and the second receiving circuit.
33 . The receiving apparatus of claim 29 ,
wherein the receiving unit includes a first receiving circuit, a second receiving circuit, and a selecting or combining unit connected to an output side of the first receiving circuit and an output side of the second receiving circuit;
wherein the high-sensitivity mode is a mode in which the selecting or combining unit performs reception using the first receiving circuit and the second receiving circuit; and
wherein the low-sensitivity mode is a mode in which the selecting or combining unit performs reception using either one of the first receiving circuit and the second receiving circuit.
34 . The receiving apparatus of claim 26 , wherein the low-sensitivity mode is implemented by restricting a current inside the receiving unit in the high-sensitivity mode.
35 . The receiving apparatus of claim 27 , wherein the low-sensitivity mode is implemented by restricting a current inside the receiving unit in the high-sensitivity mode.
36 . The receiving apparatus of claim 28 , wherein the low-sensitivity mode is implemented by restricting a current inside the receiving unit in the high-sensitivity mode.
37 . The receiving apparatus of claim 29 , wherein the low-sensitivity mode is implemented by restricting a current inside the receiving unit in the high-sensitivity mode.
38 . The receiving apparatus of claim 28 , wherein the low-sensitivity mode is implemented by decreasing the number of stages of an IF filter inside the receiving unit in the high-sensitivity mode.
39 . The receiving apparatus of claim 26 , wherein the control circuit returns the release threshold to an initial value if a state in which a judgement result according to the reception quality judging circuit is more favorable than the release threshold continues for a given time.
40 . The receiving apparatus of claim 28 , wherein the control circuit returns the release threshold to an initial value if a state in which a judgement result according to the reception quality judging circuit is more favorable than the release threshold continues for a given time.
41 . The receiving apparatus of claim 28 , wherein the reception quality judging circuit judges reception quality using an error rate of a reception signal.
42 . The receiving apparatus of claim 29 , wherein the reception quality judging circuit judges reception quality using an error rate of a reception signal.
43 . The receiving apparatus of claim 28 , wherein the reception quality judging circuit judges reception quality using a C/N ratio of a reception signal.
44 . The receiving apparatus of claim 29 , wherein the reception quality judging circuit judges reception quality using a C/N ratio of a reception signal.
45 . The receiving apparatus of claim 28 , wherein the reception quality judging circuit judges reception quality using a reception level of a reception signal.
46 . The receiving apparatus of claim 29 , wherein the reception quality judging circuit judges reception quality using a reception level of a reception signal.
47 . A receiving system comprising a decoding unit sequentially connected to the receiving apparatus of claim 26 and to an output side of the receiving apparatus, and a display unit.
48 . A receiving system comprising a decoding unit sequentially connected to the receiving apparatus of claim 27 and to an output side of the receiving apparatus, and a display unit.
49 . A receiving system comprising a decoding unit sequentially connected to the receiving apparatus of claim 28 and to an output side of the receiving apparatus, and a display unit.
50 . A receiving system comprising a decoding unit sequentially connected to the receiving apparatus of claim 29 and to an output side of the receiving apparatus, and a display unit.