Abstract: Method and apparatus for correcting the output of an onboard vehicle terrestrial magnetism sensor. An azimuth computation reference circle is obtained from the terrestrial magnetism sensor output, the circle in turn being used to correct the sensor output. When the reference circle is dislodged, the least square method is used to fine a true azimuth computation reference circle.

Abstract: In a signal recording circuit, a dither signal in a frequency band of from a frequency higher than 1/2 of the sampling frequency of a recording signal to a frequency lower than (n-1/2) of the sampling frequency (where n is an integer larger than 1) is added to the recording signal in an addition circuit, and the output of the addition circuit is subjected to analog-to-digital conversion with a frequency n times the sampling frequency.

Abstract: An MFB loudspeaker comprising a detector element mounted on a diaphragm on a specific position, i.e., a nodal line of a primary resonance mode thereof for generating a voltage proportional to a component indicative the vibratory characteristics of the diaphragm.

Abstract: At least one spiraled semi-circular shaped coil is printed on each surface of a wafer. The coil on a first surface of the wafer is arranged in such a manner that it is rotated 90 degrees with respect to the coil on a second surface thereof. In one embodiment, two such printed coils are symmetrically provided on each surface of the wafer, and the pattern of the printed coils on the first surface is arranged to be rotated 90 degrees with respect to the pattern of the printed coils on the second surface thereof. The spiraling directions of the coils on the same surface are inverse or opposite each other. The inner terminals of the coils on each surface are connected and an output is taken out from the outer terminals thereof, or vice versa. A printed coil is employed, for example, in a moving coil type pick-up cartridge.