Abstract: An analog standard cell includes a functional circuit portion and an interface circuit portion, the functional circuit portion being selected from a library of circuits having different circuit arrangements and an identical function, and the interface circuit portion being selected from a library of circuits having different circuit arrangements and an interface function, the interface circuit portion being arranged subsequent to the functional circuit to allow a predetermined output signal peak-to-peak level and a predetermined output DC bias level. The cell can be connected to a plurality of other cells to form an analog integrated circuit.

Abstract: A first reference signal whose components have the same amplitude and are symmetrical is supplied to the bases of a first and second transistors, the collectors of which are each connected to a power supply. A first resistor is connected between the emitters of the first and second transistors. A first constant current source is connected to the emitter of the first transistor. A second reference signal of a constant amplitude is supplied to the bases of a third and fourth transistors, the collectors of which are each connected to a power supply. A second resistor different in resistance from the first resistor is connected between the emitters of the third and fourth transistors. A second constant current source is connected to both the emitters of the second and third transistors, while a fourth constant current source is connected to the emitter of the fourth transistor. These first, seocnd, and third constant current sources produce the same current.

Abstract: A frequency modulator comprises an oscillator circuit, and a phase adder circuit receiving a signal derived by phase-shifting an oscillation output of the oscillator circuit by 90.degree. and multiplying the phase-shifted signal by a modulating signal, and adding the product, thereby varying an oscillation frequency of the oscillator circuit. The frequency modulator is characterized in that the amplification elements of the phase adder circuit and the oscillator circuit are connected in parallel with respect to a power source.

Abstract: An amplitude modulator is disclosed which has first and second differential pairs of transistors whose bases are supplied with a carrier signal, and a third differential pair of transistors whose collectors are respectively connected to the common emitters of the first and second differential pairs of transistors and of which one transistor is supplied at a base with a modulating signal. The emitters of the first differential pair of transistors are connected together through corresponding resistors. The collectors of two transistors which are included in the first and second differential pair of transistors and of which the bases are connected together and further connected to a load resistor.

Abstract: A frequency modulator comprises an oscillator circuit, a phase shift circuit for phase-shifting an oscillation output of said oscillator circuit by 90 degrees, a multiplier circuit for multiplying an output of the phase shift circuit by a modulating signal, and a phase adder circuit for varying an oscillation frequency of the oscillator circuit by adding the output of the multiplier circuit. The amplification elements of the phase adder circuit and the oscillator circuit are connected in parallel with respect to a power source. The multiplier circuit comprises an amplification element connected to receive the output of the phase shift circuit. A constant current source circuit is connected in series with the amplification element of the multiplier circuit and serves to vary the magnitude of current passing therethrough in accordance with the modulating signal.