Abstract: The invention relates to a circuit arrangement for generating two signals having a phase difference of approximately 90 degrees. The invention is preferably applied in the demodulator of a radio receiver. In order to shift the phase of a signal one idea of the invention is to use a distributed resistance/capacitance circuit or a distributed RC circuit (Z.sub.10, Z.sub.20) in connection with a signal amplifying means (A.sub.1, A.sub.2). The operation of the circuit is not frequency dependent and a circuit adjustment is not necessarily required in order to calibrate the phase difference, because the distributed RC circuit can provide an substantially constant phase shift of .+-.45 degrees over a wide frequency range. The whole circuit can be integrated into one component, because a distributed RC circuit is easily made on the same integrated circuit substrate as the amplifying means, and thus the circuits can be made into a small size and at low manufacturing costs.

Abstract: A 90.degree.-phase shifter which operates in condition both of high-speed and low dissipation power, and an output signal with precise 90.degree.-phase difference is capable of taking off is provided. It causes input signals with complementary relation each other to input toward input terminals. A 1/2 frequency divider is composed of bi-differential transistors Tr5 to Tr12, and load resistances R1 to R4. The 1/2 frequency divider outputs a 90.degree.-phase difference signal to output terminals 11 to 14 based on collector current of signal input transistors Tr1 and Tr2. The collector current corresponds to the input signal. A duty ratio monitoring load 2 converts these collector currents into voltage. A low-pass filter 3 takes off a DC component corresponding to an offset from 50%-duty ratio of an input voltage from the converted voltage. A DC component amplifier amplifies the DC component thus performing feedback to the input terminals 8 and 9.

Abstract: A high frequency, current mode, single-ended-to-differential signal converter with low input impedance constant to very high frequencies and a balanced output signal even for large signals. A wide range of input voltages may be accommodated and a d.c. offset correction added. A circuit for achieving a precise fifty percent duty cycle digital signal is disclosed. A circuit for ensuring a 90.degree. phase differential between two signals needed for quadrature multiplication is disclosed. Unusual precision in phase control of the quadrature signals needed for modulation and demodulation of wireless signals is obtained by the use of feedback circuits in both the duty cycle generator and phase shifter.

Abstract: A quadrant detector circuit (400) has a comparator (442) having a pair of inputs (438, 440). A first (438) of the pair of inputs (438, 440) is coupled to an in-phase signal (434) and a second (440) of the pair of inputs (438, 440) is coupled to a quadrature phase signal (436). A sample counter (448) has a reset (446) coupled to an output (444) of the comparator (442). A controllable switch (456) has a selection input (454) coupled to an output (452) of the sample counter (448). The controllable switch (456) is capable of switching between a local oscillator signal (458) and an inverse local oscillator signal (460).

Abstract: A phase shifting circuit that may be used as part of a quadrature clock generator. The phase shifting circuit comprises a triangle wave generator coupled to receive an input reference signal. The triangle wave generator outputs a pair of complementary triangle wave signals in response to the input reference signal. A comparator having a pair of inputs is coupled to receive the pair of complementary triangle wave signals. The comparator outputs an output signal having a predetermined phase relationship with the input reference signal in response to a comparison between the pair of complementary triangle wave signals.

Abstract: An active quadrature power splitter having low power consumption is small in size and is inexpensive, for obtaining two output signals of which the phase difference is 90 degrees. Since the active quadrature power splitter operates as a microwave amplifier for obtaining two amplified microwave outputs having an equal magnitude and a phase difference of 90 degrees by using a matching circuit of the amplifier, a power gain can be obtained. Also, since a single FET or HBT is used and two output signals are generated in an output impedance matching circuit, the circuit becomes simplified. Therefore, the circuit can be easily implemented in a monolithic microwave IC and the chip size can be reduced.

Abstract: The correction circuit comprises a first quadrature phase comparator intended to receive as input two signals which are desired to be in quadrature and to have equal amplitudes. Phase adjustment means are firstly intended to correct the phase of at least one of the signal to re-establish a phase difference of 90.degree. therebetween. The correction circuit further comprises means to effectuate the sum and the difference of the signals which it receives as input and to supply the sum and the difference to a second quadrature phase comparator intended to supply as output a second error signal representative of the difference of the effective phase shift of these calculated signals and 90.degree.. The second error signal is finally supplied to amplitude adjustment means intended to correct the amplitude of at least one of said signals.

Abstract: Disclosed is an integrated circuit comprising a balanced set of inputs and a phase splitting circuit. The phase splitting circuit has a first input terminal that is coupled to the balanced set of inputs and a second input terminal that is coupled to the balanced set of inputs. The phase splitting circuit further comprises a balanced phase shifting network, a first set of output terminals, and a second set of output terminals. The balanced phase shifting network is coupled to the first: input terminal and the second input terminal. The first set of output terminals provides a voltage representative of a first voltage across a resistive portion of the balanced phase shifting network in response to an input voltage at the balanced set of inputs. The second set of output terminals provides a voltage representative of a second voltage across a reactive portion of the balanced phase shifting network in response to the input voltage at the balanced set of inputs.

Abstract: An accurate phase shifting circuit providing two analog signals having a 90-degree phase shift between them from a single sampled-data input without the need for components external to a monolithic integrated circuit. A combination of two discrete-time circuits achieves the required 90-degree phase relationship over a broad frequency region. Several sample-and-hold circuits and multiplexors are used to produce two discrete-time versions of the analog input signal. Subtracting that older sample from the most-recent sample yields a forward difference signal and adding the most recent and the older samples produces a forward average signal. The phase difference between any single-frequency component of the forward difference and forward average signals is always 90 degrees. A pair of matched filters serves to reconstruct the sampled analog waveforms and to remove unwanted high-frequency noise in the +90.degree. output signal.