Circuit and method for distinguishing between an ofdm signal and a radar signal

A circuit for distinguishing between a first signal having a relatively large instantaneous bandwidth and a second signal having a relatively small instantaneous bandwidth, the circuit having an input terminal for receiving an input signal and comprising:

• at least first and second bandpass filters connected to the input terminal and each having a passband of width substantially less than said relatively large instantaneous bandwidth and substantially greater than said relatively small instantaneous bandwidth, the passbands of the first and second filters being substantially non-overlapping,
• a multiplier for multiplying a power level of an output signal of the first filter with a power level of an output signal of the second filter to form a power product signal, and
• a power level comparator for comparing the power level of the power product signal with a threshold level and providing an indicating signal in a first state if the power level of the power product signal exceeds the threshold level and otherwise providing said indicating signal in a second state.

A method for determining whether an input signal is an orthogonally frequency division multiplexed (OFDM) signal or a radar signal, the method comprising:

• applying at least first and second bandpass filtering operations to the input signal, each filtering operation having a passband of width substantially less than a relatively large instantaneous bandwidth characteristic of an OFDM signal and substantially greater than a relatively small instantaneous bandwidth characteristic of a radar signal, the passbands of the first and second filtering operations being substantially non-overlapping,
• multiplying power levels of output signals of the first and second filtering operations to form a power product signal, and
• comparing the power level of the power product signal with a threshold level and providing an indicating signal in a first state if the power level of the power product signal exceeds the threshold level and otherwise providing said indicating signal in a second state.

A method for determining whether an input signal is a first signal having a relatively large instantaneous bandwidth or a second signal having a relatively small instantaneous bandwidth, the method comprising:

• applying at least first and second bandpass filtering operations to the input signal, each filtering operation having a passband of width substantially less than said relatively large instantaneous bandwidth and substantially greater than said relatively small instantaneous bandwidth, the passbands of the first and second filtering operations being substantially non-overlapping,
• multiplying a power level of an output signal of the first filtering operation with a power level of an output signal of the second filtering operation to form a power product signal, and
• comparing the power level of the power product signal with a threshold level and providing an indicating signal in a first state if the power level of the power product signal exceeds the threshold level and otherwise providing said indicating signal in a second state.