Abstract: A wireless transmission system which adaptively selects a plurality of modulation schemes according to variations in a propagation path characteristic, capable of estimating the modulation scheme of a received signal more easily with a substantially simple configuration. This system adds priority order to modulation schemes to be candidates for modulation scheme estimation processing, carries out estimation processing on modulation schemes one by one in descending order of priority and confirms the modulation scheme of the received signal when predetermined likelihood is obtained.

Abstract: A waveform generator comprises waveform generating means for generating a waveform signal band-limited using a first band limitation characteristic in accordance with the input signal series, memory means for storing in advance a difference signal between a waveform signal band-limited using the first band limitation characteristic for the input signal series and a waveform signal band-limited using a second band limitation characteristic for the input signal series and outputting the difference signal in accordance with the input signal series, adding means for adding a waveform signal from the waveform generating means to a difference signal from the memory means and outputting the signal band-limited using the second band limitation characteristic, and selector switch means for selectively outputting either a waveform signal from the waveform generating means or a waveform signal from the adding means.

Abstract: A radio reception apparatus and a reception filtering method that effectively cancel interference component from a received signal and improve reception performance. A variable coefficient digital filter 110 changes tap coefficients for optimal filter characteristics and cancels inter-symbol interference. Additionally, the variable coefficient digital filter 110 uses tap coefficients determined by a tap coefficient control section 1124. A filter adjusting section 112 determines the tap coefficients of the variable coefficient digital filter 110 according to the modulation scheme used in the received signal. More specifically, a modulation scheme determining section 1122 estimates the modulation scheme using the known signal patterns included in the received signal, and outputs a modulation scheme selection signal that represents the estimated modulation scheme.

Abstract: A wireless transmission system which adaptively selects a plurality of modulation schemes according to variations in a propagation path characteristic, capable of estimating the modulation scheme of a received signal more easily with a substantially simple configuration. This system adds priority order to modulation schemes to be candidates for modulation scheme estimation processing, carries out estimation processing on modulation schemes one by one in descending order of priority and confirms the modulation scheme of the received signal when predetermined likelihood is obtained.

Abstract: While a current of a constant current source 503 is equally divided to a plurality of current paths so as to produce a unit current, switches which are series-connected to the respective current paths are controlled by a switch circuit 504 in response to a digital input signal. As a result, since both output currents 505 and 506 whose unit currents are variable can be obtained, a total number of circuit components is reduced, so that not only an occupied area may be reduced, but also resolution in the vicinity of a center may be improved.

Abstract: A waveform generator comprises waveform generating means for generating a waveform signal band-limited using a first band limitation characteristic in accordance with the input signal series, memory means for storing in advance a difference signal between a waveform signal band-limited using the first band limitation characteristic for the input signal series and a waveform signal band-limited using a second band limitation characteristic for the input signal series and outputting the difference signal in accordance with the input signal series, adding means for adding a waveform signal from the waveform generating means to a difference signal from the memory means and outputting the signal band-limited using the second band limitation characteristic, and selector switch means for selectively outputting either a waveform signal from the waveform generating means or a waveform signal from the adding means.

Abstract: While a current of a constant current source 503 is equally divided to a plurality of current paths so as to produce a unit current, switches which are series-connected to the respective current paths are controlled by a switch circuit 504 in response to a digital input signal. As a result, since both output currents 505 and 506 whose unit currents are variable can be obtained, a total number of circuit components is reduced, so that not only an occupied area may be reduced, but also resolution in the vicinity of a center may be improved.