Abstract: A measuring apparatus and a method is provided for measuring performance characteristics of a recording unit including a circular recording medium on which one track is divided into a plurality of sectors, where the recording unit records a data signal on the recording medium by using a magnetic head. A mechanism device including micro actuator and a piezo-electric stage moves the magnetic head in a direction substantially perpendicular to a circumferential direction of the recording medium in response to a control signal. The measuring apparatus writes a write signal for respective sectors while moving the magnetic head by outputting the control signal having different levels corresponding to respective sectors to the mechanism device, and reads out the written write signal, then measuring a read-out write signal as a read signal relative to a position of the magnetic head.

Abstract: The invention is directed toward a measuring apparatus for measuring performance characteristics of a recording unit including a recording medium on which one track is divided into a plurality of sectors. The measuring apparatus includes a writing means for writing a write signal with a write parameter, a first control means for changing the write parameter value for respective sectors, a reading means for reading out the write signal written by the writing means with a read parameter and measuring the read-out write signal as a read signal, and a second control means for controlling the read parameter so as to produce predetermined read parameter values for respective sectors.

Abstract: In apparatus that measures the characteristics of the read-out signals from memory media, in the prior art, phase control of the clock signals for synchronized sampling of the measurement apparatus was performed by using the read-out signals. Synchronization discrepancies and inability to perform synchronization were produced due to the quality of the read-out signals. In the invention, a Logical processing part generates selection signals that control the selection of samples with phase information, for performing synchronization, from test signals of a recording part, which records the same signal train as the test signal train written onto the memory medium. By the control of these selection signals, samples with phase information for performing synchronization are selected from the sample train output from an A/D converter through an equalizer; these samples pass through a selection part and a control clock generating part by means of the processing of a feed-back processing part.

Abstract: A circuit adjusts the gain, direct-current (DC) component, and transient response of input signals to provide suitable output signals for a connected signal processor. The circuit includes a gain and DC component control circuit, which controls the amplitude and DC offset level of an input signal; an A/D converter, which performs A/D conversion on the output of the gain and DC component control circuit; and an equalization filter, which is connected to the output of the A/D converter. The amplitude distribution of the output waveform of the equalization filter is measured, and the gain and DC component control circuit is controlled on the basis of said measured value, in order to assure that the output of the equalization filter is suitable for a connected signal processor.

Abstract: A non-integer frequency divider is provided that can perform switching of a frequency division ratio setting at high speed in order to improve the phase noise of frequency synthesizers and raise their response speeds. The frequency divider is a non-integer frequency divider that performs frequency division with frequency division ratios that contain decimal fraction, and includes a first frequency divider which can be set to a number of integer frequency division ratios; a second frequency divider (i.e., a shift register); a bit selector; a CA value generator; and a .SIGMA..DELTA. modulator. Non-integer frequency division is realized by switching the settings of the frequency division ratio and the period number of the frequency division output signal of the first frequency divider and the setting of the frequency division ratio of the second frequency divider.

Abstract: A transducer and a mixer with a double-balanced output according to the current invention are capable of frequency conversion in a microwave band with low distortion. The transducer or the mixer has symmetry of wirings. One side of a printed circuit board has branched strip lines and a single strip line whose base portion serves as an RF input terminal, and the other side of the printed circuit board has twin-branched ground strips and a bridge-shaped ground strip. The combination of the branched strip lines and the twin-branches strips, and the combination of the single strip line and the bridge-shaped ground strip serve as a transducer. One pair of diagonal terminals of the symmetrical diode ring is connected to the base portion of the branched strip lines. The other pair of diagonal terminals is connected to the tip of the single strip line. The diode ring is connected to a transducer. One winding thereof is supplied with a local oscillator.

Abstract: The present invention provides a high frequency transformer capable of stable operation from DC to high frequency. Additionally the present invention provides a mixer with low insertion loss and low distortion, in which a common mode choke is removable from an input portion thereof. To form the stable high frequency transformer according to the present invention, a short circuiting pattern couples two strip lines together to form a U-shaped pattern on a printed circuit board and a lead wire is insulatedly coupled to each strip line and short-circuited at the tip of the U-shape. According to the present invention, a local oscillator is connected to a first port of the high frequency transformer, a diode switch is connected to a second port of the high frequency transformer, thereby serving as an IF output terminal, and a third port is formed at the short-circuiting pattern, thereby serving as the RF input terminal.