Anritsu Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Tomohisa Okada

Takayuki Saito

Chihiro Tagawa

Takashi Seike

Yuji Honma

Mamoru Akada

Embodiments in accordance with the present invention provide a disk drive and a control method in the disk drive which can obtain good recording performance by amplifying the write current according to the recording method and the recording frequency. A HDD in accordance with an embodiment of the present invention comprises a write current supply section and a write head. The write current supply section generates a write signal for recording to a disk and, based on the write current, generates a write current I. The write head records data to the disk by the write current I. The write current supply section comprises a write channel to generate a write signal, a write driver to generate a write current from the write signal, a high frequency pattern extracting circuit to extract high frequency pattern parts from the write signal, and a write driver to generate a write current Ifrom the extracted high frequency pattern parts. The write currents and are added up and supplied to the write head as the write current whose magnitude is amplified only when the frequency is high.

Write current boosted head amplifier

An analysis operation section uses a digital signal converted by an A/D converter, and performs frequency analysis for a modulation signal and modulation analysis for the modulation signal selected by a signal selection circuit in order to modulate/analyze a digital signal level of the modulation signal as an analysis object outputted from a level converter. A controller instructs the analysis operation section to execute an analysis instruction inputted via an operation input section, sends a selection instruction to the signal selection circuit in accordance with a modulation type of the inputted modulation signal, and sets a bandwidth of an RBW filter in accordance with the modulation type when the modulation signal having a band limited by the RBW filter is selected as the modulation signal inputted to the A/D converter, and the modulation analysis instruction is inputted.

Modulation signal analysis apparatus

An inversion in-phase component and a non-inversion in-phase component of a modulation signal inputted from a quadrature modulation section of a sample machine captured in a pair of signal lines, and an inversion quadrature component and a non-inversion quadrature component of the modulation signal, are computed by a pair of computers, respectively. In addition, these components are analog/digital converted at a pair of analog/digital converting sections, and then, are stored in a waveform storage memory. A modulation characteristics analyzing section performs predetermined computation processing of the storage data, thereby analyzing modulation characteristics of the modulation signal. A balance/imbalance switching section is provided at each one of the pair of signal lines, and the signal lines are grounded, whereby a state for transmitting a modulation signal of a balance transmission format is switched to a state for transmitting a modulation signal of an imbalance transmission format.

Modulation analyzing apparatus with balance/imbalance converter

A radio communication analyzer can test a radio device under test which corresponds to one of a plurality of types of digital communication systems in accordance with the digital communication system to which the radio device under test corresponds. The radio communication analyzer includes a modulation section, a demodulation section, a modulation/demodulation processing section, and a control section. The modulation section has a first rewritable memory, and converts modulation data indicating the contents of a first test signal to be transmitted to the radio device under test into a digital modulated signal by executing a program written in the first memory. The demodulation section has a second rewritable memory, and generates demodulated data from a second test signal received from the radio device under test by executing a program written in the second memory. The modulation/demodulation processing section has a third memory. The modulation/demodulation processing section generates data to be input to the modulation section and processes the demodulated data obtained by the demodulation section on the basis of a protocol for the digital communication system used by the radio device under test by executing a program written in the third memory. The control section reads out program data corresponding to the respective types of digital communication systems and stored in a storage unit and writes the program data in the first, second, and third memories.

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Kanagawa, Japan

Tomohisa Okada