Shifting a frequency band of an interference signal out of a pass band of a signal path

A remote antenna unit, comprising:

• a first signal path configured to carry, during a first period, a first information signal having a first frequency;
• and
• a first frequency-shifting circuit coupled to the first signal path and configured to:
• receive a first control signal;
• shift the first frequency of the first information signal by a second frequency in response to the first control signal having a first control value;
• and
• shift a third frequency of a first interference signal on the first signal path during a second period by a fourth frequency in response to the first control signal having a second control value;
• a second signal path configured to carry, during the second period, a second information signal having the first frequency;
• and
• a second frequency-shifting circuit coupled to the second signal path and configured to:
• receive a second control signal
• shift the first frequency of the second information signal by a fifth frequency in response to the second control signal having a third control value;
• and
• shift a sixth frequency of a second interference signal on the second signal path during the first period by a sixth frequency in response to the second control signal having a fourth control value.

A distributed antenna system, comprising:

• a master unit;
• and
• at least one remote antenna unit each coupled to the master unit and including:
• a first signal path configured to carry, during a first period, a first information signal having a first frequency, and
• a first frequency-shifting circuit coupled to the first signal path and configured to:
• receive a first control signal;
• shift the first frequency of the first information signal by a second frequency in response to the first control signal having a first control value;
• and
• shift a third frequency of a first interference signal on the first signal path during a second period by a fourth frequency in response to the first control signal having a second control value;
• wherein the first frequency-shifting circuit includes an output node configured to carry the frequency-shifted first information signal during the first period and the frequency-shifted interference signal during the second period;
• wherein the first signal path includes:
• a bandpass filter having an input node coupled to the output node of the first frequency-shifting circuit and having an output node;
• an amplifier having an input node coupled to the output node of the bandpass filter and having an output node;
• and
• an antenna coupled to the output node of the amplifier.

A communication system, comprising:

• a distributed antenna system, including:
• a master unit;
• at least one remote antenna unit each coupled to the master unit and including:
• a first signal path configured to carry, during a first period, a first information signal having a first frequency;
• and
• a first frequency-shifting circuit coupled to the first signal path and configured to:
• receive a first control signal;
• shift the first frequency of the first information signal by a second frequency in response to the first control signal having a first control value;
• and
• shift a third frequency of a first interference signal on the first signal path during a second period by a fourth frequency in response to the first control signal having a second control value;
• a second signal path configured to carry, during the second period, a second information signal having the first frequency;
• and
• a second frequency-shifting circuit coupled to the second signal path and configured to:
• receive a second control signal
• shift the first frequency of the second information signal by a fifth frequency in response to the second control signal having a third control value;
• and
• shift a sixth frequency of a second interference signal on the second signal path during the first period by a sixth frequency in response to the second control signal having a fourth control value;
• and
• at least one base station coupled to the distributed antenna system.