Abstract: An amplifier circuit for amplifying output signal from the crystal oscillator circuit is connected to the output side of the crystal oscillator circuit. The amplifier circuit amplifies the difference between the output voltage of the crystal oscillator circuit and the input voltage of a CMOS inverter of the crystal oscillator circuit. For example, a differential amplifier is connected to the output side of the crystal oscillator circuit, then the output voltage of the crystal oscillator circuit and the input voltage of the CMOS inverter are connected to the inputs of the differential amplifier.

Abstract: It is an object of the present invention to provide a method for determining the load capacitance CL of an oscillator circuit having a low load capacitance. To attain the object, we provide a method for determining the load capacitance CL of an oscillator circuit, wherein, when a drive current and a load capacitance of the oscillator circuit with a negative resistance RL1 are Ios1 and CL1, respectively, a load capacitance CL2 for changing the drive current of the oscillator circuit to Ios2 (<Ios1) is given by: CL2=CL1*(Ios2/Ios1)1/2.

Abstract: An amplifier circuit for amplifying output signal from the crystal oscillator circuit is connected to the output side of the crystal oscillator circuit. The amplifier circuit amplifies the difference between the output voltage of the crystal oscillator circuit and the input voltage of a CMOS inverter of the crystal oscillator circuit. For example, a differential amplifier is connected to the output side of the crystal oscillator circuit, then the output voltage of the crystal oscillator circuit and the input voltage of the CMOS inverter are connected to the inputs of the differential amplifier.

Abstract: According to the invention, two of three design values, i.e., the negative resistance RL, load capacitance CL and drive current Ios of a crystal oscillator circuit including a crystal resonator are determined to determine the remaining one design value from a relation equation or relation graph. As a result, reducing the CL of the crystal oscillator circuit allows the drive current Ios to be reduced, achieving reduced power consumption of the crystal oscillator circuit.

Abstract: There is provided an oscillation circuit including a crystal vibrator that is connected between input and output terminals of a CMOS inverter making up the oscillation circuit; an input wiring line that includes a crystal vibrator-side input terminal connected to an input terminal pad of the CMOS inverter; an output wiring line that includes a crystal vibrator-side output terminal connected to an output terminal pad of the CMOS inverter; a ground power source wiring line that includes a crystal vibrator-side ground power source terminal; and a capacitative element that is connected between the input wiring line and the ground power source wiring line, and between the output wiring line and the ground power source wiring line, wherein the ground power source wiring line is disposed at least a part of between the input wiring line and the output wiring line.

Abstract: There is provided an oscillation circuit using a crystal vibrator including means A for obtaining an oscillation activation time Ts (Ts0) from an oscillation margin M by using a relational equation between the oscillation activation time Ts and the oscillation margin M or a relational graph thereof; means B for obtaining a relational equation between the oscillation activation time Ts and a load capacitance CL in an arbitrary driving current value Ios from the relational equation between the oscillation activation time Ts and the load capacitance CL, and the driving current value Ios; and means C for determining the load capacitance CL corresponding to the oscillation activation time Ts0 obtained by the means A, by using the relational equation between the oscillation activation time Ts and the load capacitance CL, which is obtained by the means B.

Abstract: In a circuit including a CMOS inverter (inverting amplifier) (IV02), a floating capacitance resulting from the circuit and peripheral interconnections thereof is Cs, a capacitive element (Cg) is connected to the input side of the CMOS inverter (inverting amplifier) (IV02), a capacitive element (Cd) is connected to the output side thereof, and the capacitances of the capacitive element (Cg) and the capacitive element (Cd) are determined (tuned) so that a load capacitance (CL) of a piezoelectric vibrator (X2) satisfies a relational expression “CL=Cs+Cg×Cd/(Cg+Cd)”. By determining the capacitances of the capacitive element (Cg) and the capacitive element (Cd) in this way, it is possible to improve the oscillation frequency stability with respect to a variation in capacitance value of the load capacitance (CL) in a region of a low load capacitance (CL) (for example, 3 pF).

Abstract: A communication apparatus capable of being connected to networks of a plurality of types, comprising a network discrimination table for discriminating an incoming network of a call setup message, a routing table for selecting an outgoing network of the call setup message, and a control unit for rewriting the contents of an address field and a sub-address field of the received call setup message on the basis of the routing table and transmitting the resultant message to the outgoing network.