Abstract: A method and apparatus of calibrating electronic scales for the horizontal axis of an oscilloscope is provided. For each of two electronic scales or cursors, output voltages of a horizontal deflection circuit are generated. A measurement is made to determine a time interval in which the voltage of a sweep waveform, generated by a sweep waveform generator and appearing at the output of the horizontal deflection circuit, passes the two output voltages. The slope of the sweep waveform generated by the sweep waveform generator is adjusted such that the time interval coincides with a target time interval.

Abstract: An interdigital bandpass filter is provided which presents improved performance and is easy to manufacture. The filter is provided with a resonator plate which includes a plurality of resonator elements formed integrally with the resonator plate. For defining a space for accommodating these resonator elements, spacer plates are formed with respective openings. The filter is assembled by stacking the spacer and resonator plates and case plates and securing them to each other. Input/output conductors are coupled to the resonator elements through coaxial line coupling portions which are provided in such a manner that they extend in directions intersecting with the plane of the resonator plate toward the accommodating space.

Abstract: Voltage control means output to a variable resistance part 2 a control voltage proportionate to an error between an input detection signal of an input terminal T.sub.i of a source follower field-effect transistor 1 and an output detection signal of an output-side transistor 5. Although said variable resistance part 2 changes its resistance value in accordance with a control voltage, a drain current flowing from the field-effect transistor to said variable resistance part is maintained constant by a constant-current source 3. Thus, an output voltage of the output side transistor changes in accordance with said error, thereby controlling the input detection voltage and the output detection voltage to be constantly the same.

Abstract: A television signal level meter is provided which is capable of simultaneously displaying levels for a multitude of television channels in a scale having a variable dynamic range. The television meter includes a level image forming means for displaying signal levels of a multitude of channels, a scale forming means for forming a scale suitable for simultaneously displaying the signal levels of the channels, and an image forming means for displaying channel numbers associated with the channels.

Abstract: A method and apparatus used for determining phasing correlation between left-channel and right-channel signals of a stereophonic audio signal is provided. The determination of the phase correlation is facilitated by deriving centrally localized components contained in the audio signal to provide an indication representative of phase correlation existing between the left-channel and right-channel signals.

Abstract: A method and apparatus for calibrating the scale of an X-Y display device is provided wherein at least two intersecting linear loci are formed and displayed on the screen of the device to show the X and Y axes of effective coordinates of the display device. The display of intersecting loci facilitates adjustments of the device enabling effective coordinates to be coincided with the coordinates of the scale.

Abstract: A variable gain amplifier is provided which includes a pair of common emitter circuits. A resistance between the collectors of a pair of transistors included within the common emitter circuits is reduced by a variable resistance used for DC level correction which is connected in parallel with a variable resistance used for gain adjustment which is connected between the collectors, thereby reducing the degree of correlation between the width of a variable range of gain and a bandwidth.

Abstract: A circuit arrangement is provided for phase compensation for a feedback amplifier circuit which has a variable gain depending upon the level of an input, so that a broadened frequency range in which the gain is substantially constant with respect to any given level of the input is attained. Also, logarithmic converter circuits in which such phase compensation is performed are provided.

Abstract: A measuring instrument for SC/H phase of a composite video signal is provided in which a phase comparison is made between at least a portion of a color burst extracted from the video signal and a continuous subcarrier frequency signal that is phase-locked to the leading edge of the horizontal sync phase so as to determine the particular SC/H pulse. The instrument includes a display device which provides a display concerning the measured SC/H phase in the form of characters and/or a waveform.

Abstract: In a method and a vector scope for measuring distortion of a subcarrier signal causing color aberration of a color television signal, a carrier chrominance signal resulting from a color bar signal transmitted in a transmission system and a reference carrier chrominance signal including a signal determining levels of the amplitude and phase distortions of said carrier chrominance signal are demodulated through the same demodulating device and color difference signals thus obtained are displayed in vector, whereby only the distortion of the subcarrier by the transmission system is measured independently of the influence of the distortion of the vector scope itself.