Abstract: A negative pressure controller controls a negative pressure in a vacuum chamber of a vacuum booster by controlling a negative pressure supplier connected to the vacuum chamber. The negative pressure controller includes: negative pressure sensors each configured to detect the negative pressure in the vacuum chamber; and a negative-pressure-supplier controller configured to actuate the negative pressure supplier when one of output values of the negative pressure sensors which is nearest to an atmospheric pressure among the output values becomes nearer to an atmospheric pressure than a first threshold value. The negative-pressure-supplier controller is configured to stop the negative pressure supplier when at least two output values of the output values of the negative pressure sensors become nearer to a vacuum than a second threshold value.

Abstract: A negative pressure controller controls a negative pressure in a vacuum chamber of a vacuum booster by controlling a negative pressure supplier connected to the vacuum chamber. The negative pressure controller includes: negative pressure sensors each configured to detect the negative pressure in the vacuum chamber; and a negative-pressure-supplier controller configured to actuate the negative pressure supplier when one of output values of the negative pressure sensors which is nearest to an atmospheric pressure among the output values becomes nearer to an atmospheric pressure than a first threshold value. The negative-pressure-supplier controller is configured to stop the negative pressure supplier when at least two output values of the output values of the negative pressure sensors become nearer to a vacuum than a second threshold value.

Abstract: The invention relates to a control device for an electrically-driven vacuum pump. The control device stops operation of an electrically-driven vacuum pump for generating negative pressure in a negative pressure chamber of a brake booster when the vacuum pump is operated and a gradient of increasing of a booster negative pressure representing a magnitude of a difference between pressure in the negative pressure chamber and the atmospheric pressure is smaller than or equal to a predetermined stop gradient threshold.

Abstract: The invention relates to a control device for an electrically-driven vacuum pump. The control device stops operation of an electrically-driven vacuum pump for generating negative pressure in a negative pressure chamber of a brake booster when the vacuum pump is operated and a gradient of increasing of a booster negative pressure representing a magnitude of a difference between pressure in the negative pressure chamber and the atmospheric pressure is smaller than or equal to a predetermined stop gradient threshold.

Abstract: A magnetic recording apparatus having a plurality of magnetic heads (111-118) by which data is written on and read from a magnetic medium (121-123) has a timing correction unit (3) that controls a suitable timing according to a predetermined characteristic of a selected magnetic head or disk apparatus and the density of logical ONE states in the data so that the data will be written on the magnetic medium under the timing controlled by the timing correction unit. Timing correction may also be provided according to whether the head is an inner or an outer head.

Abstract: A waveform equivalent circuit for correcting the asymmetry of the rising and falling slopes of an isolated signal waveform retrieved from a magnetic recording medium so as to restore an acute, symmetric isolated waveform. In operation, the input signal is phase-shifted and attenuated, and then added to the input signal to produce a smaller double peaked waveform, which is modified with an inverted and attenuated version of the input waveform. The input signal waveform is subtracted from the modified double peaked signal waveform to diminish both slope sections, and an acute, symmetric original signal waveform is recreated.