1. A wireless communication apparatus, comprising:
a baseband circuit;
a transmitter that uses a baseband signal outputted by the baseband circuit as an input signal, modulates the input signal by quadrature modulation, amplifies the modulation signal, and outputs a transmitted signal;
an antenna that transmits and receives a radio wave;
a receiver that demodulates a received signal from the antenna by quadrature demodulation, and outputs a baseband signal that corresponds to the received signal;
a selector that supplies the transmitted signal outputted by the transmitter to the antenna, and supplies the received signal from the antenna to the receiver; and
a local signal generation circuit that generates a local signal for use in the quadrature modulation performed by the transmitter and the quadrature demodulation performed by the receiver,
wherein the transmitter comprises:
a first quadrature modulator that modulates the input signal by quadrature modulation into a signal in which a frequency band is included in a first frequency band;
a first amplifier that amplifies a modulation signal outputted by the first quadrature modulator;
a second amplifier that amplifies an output signal of the first amplifier;
a second quadrature modulator that modulates the input signal by quadrature modulation into a signal in which a frequency band is included in a second frequency band;
a third amplifier that amplifies a modulation signal outputted by the second quadrature modulator; and
a fourth amplifier that amplifies an output signal of the third amplifier by electric power,
wherein each of the first amplifier and the third amplifier performs a limiting operation when a modulation format is constant envelope modulation, and performs a linear operation when the modulation format is non-constant envelope modulation,
wherein a gain of each of the first amplifier and the third amplifier is controllable independently of a switching operation between the limiting operation and the linear operation,
wherein, when operating in the first frequency band, the first quadrature modulator, the first amplifier, and the second amplifier enter an operating state and the second quadrature modulator, the third amplifier, and the fourth amplifier enter a non-operating state, and
wherein, when operating in the second frequency band, the first quadrature modulator, the first amplifier, and the second amplifier enter the non-operating state, and the second quadrature modulator, the third amplifier, and the fourth amplifier enter the operating state.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for providing a magnetic read transducer including a magnetoresistive sensor, wherein the magnetoresistive sensor includes a cap layer overlaying a free layer, the method comprising:
situating the cap layer with a first thickness to absorb boron from the free layer to the cap layer; annealing the magnetoresistive sensor;
diffusing boron from the free layer and absorbing boron by the cap layer during the annealing the magnetoresistive sensor;
forming the cap layer as amorphous, the amorphous cap layer including titanium boride, and situating the amorphous cap layer to at least substantially inhibit the free layer from crystallizing in an orientation other than a body center cube crystal structure with a 100 plane (bcc (100)); and
reducing the cap layer thickness to a second thickness, after annealing the magnetoresistive sensor.
2. The method as in claim 1, wherein the cap layer includes one of elemental titanium, hafnium, zirconium, niobium, tantalum, and ruthenium.
3. The method as in claim 1, wherein, before annealing the magnetoresistive sensor, the free layer includes i.) CoFe, and ii.) at least one of CoB, CoB and Fe, and Co1-xFexBy, wherein x is 0 to 0.9, and y is 0.1 to 0.25.
4. The method as in claim 1, wherein the first thickness is in a range of 40 angstroms to 200 angstroms, and the second thickness is either 20 angstroms, or in a range of 5 angstroms to 50 angstroms.
5. The method as in claim 1, wherein reducing the cap layer thickness to the second thickness comprises reducing the cap layer thickness to less than 20angstroms, and less than one-half of the first thickness.
6. The method as in claim 1, further comprising overlaying the cap layer with a ruthenium layer, and overlaying the ruthenium layer with a tantalum layer, before annealing the magnetoresistive sensor.
7. The method as in claim 1, further comprising overlaying the cap layer with a layer, after reducing the cap layer thickness to the second thickness.
8. The method as in claim 7, wherein the layer overlaying the cap layer includes a nickel-iron layer overlaying the cap layer, and a ruthenium layer or a tantalum layer overlaying the nickel-iron layer.
9. The method as in claim 1, wherein reducing the cap layer thickness comprises etching the cap layer via one of ion-beam milling, plasma etching, and chemical wet etching.
10. A method for providing a magnetic read transducer including a magnetoresistive sensor, wherein the magnetoresistive sensor includes a cap layer overlaying a free layer, the method comprising:
forming the cap layer as amorphous, the amorphous cap layer including titanium boride; and situating the amorphous cap layer to at least substantially inhibit the free layer from crystallizing in an orientation other than a body center cube crystal structure with a 100 plane (bcc (100)).
11. The method as in claim 10, wherein the cap layer includes one of elemental titanium, hafnium, zirconium, niobium, tantalum, and ruthenium.
12. The method as in claim 10, wherein the free layer includes i.) CoFe, and ii.) at least one of CoB, CoB and Fe, and Co1-xFexBy, wherein x is 0 to 0.9, and y is 0.1 to 0.25.