Abstract: A transceiver is disclosed having a zero intermediate frequency to low intermediate frequency receiver and a direct upconversion transmitter. Calibrations may be performed to minimize direct current voltage offset and in-phase and quadrature-phase path mismatch after downconversion. Automatic gain control is performed prior to downconversion and after upconversion to minimize the introduction of mismatch.

Abstract: The direct current circuit comprises first to fourth mixers to which high frequency signals and a local oscillation signal having an equal frequency to that of the high frequency signal are inputted, and first and second multiplexer circuits which output components of a sum of two signals. A phase of the high frequency signals which are inputted to the first and second mixers and a phase of the high frequency signals which are inputted to the third and fourth mixers are made to differ from each other by &pgr;. A phase of the local oscillation signals which are inputted to the first and third mixers and a phase of the local oscillation signals which are inputted to the second and fourth mixers are made to differ from each other by &pgr;/2.

Abstract: The method includes an adjustment phase in which a filtering device is operated as an oscillator, the frequency of oscillation of the filtering device is determined, and the characteristics of the filtering device are corrected with respect to the determined oscillation frequency and to a pre-established relation between the frequency of oscillation and the theoretical cutoff frequency, in such a way as to confer upon the filtering device a cutoff frequency equal to the theoretical cutoff frequency to within a tolerance. After the adjustment phase, a working phase takes place in which the filtering device carries out its filtering function.

Abstract: A direct conversion receiver for receiving a first input signal and directly downconverting it to baseband frequencies. The receiver includes a frequency translator which is responsive to a phase-split input signal having 2n components, wherein n is an integer greater than 1. The phase-split signal has a period T which is about n times the period of the first input. The frequency translator alternates, at a rate of about 2n/T, between switching the first input signal to a first output, and switching the first signal to a second output. A preprocessor is available to improve the switching characteristics of the phase-split input signal.

Abstract: A dual-band receiver for a wireless communication device having multi-slot capability. A first oscillator generates a relatively high frequency traffic LO signal. A second oscillator generates a first relatively low frequency signal, and a third oscillator generates a fixed low frequency signal. A first mixer mixes the first and fixed low frequency signals to produce a relatively high frequency monitor LO signal. A switch selects the traffic LO signal when the receiver is in a traffic slot and the monitor LO signal when the receiver is in a monitor slot. The selected LO signal is provided to a second mixer along with the received signal to produce a first IF signal. A third mixer mixes the first IF signal and the fixed frequency signal to produce an output signal.

Abstract: A receiving unit that reduces the amount of power consumed for detecting the timing of each of a plurality of paths via which received signals were received. A receiving section receives signals sent from a base station and transmitted via a plurality of paths. A path detecting section detects the timing of each of the plurality of paths via which the received signals received by the receiving section were transmitted. A path detection range setting section sets a range where a path is detected by the path detecting section on the basis of information indicative of path timing detected by the path detecting section.

Abstract: The switchable up-conversion loop device for a transmitting stage of a mobile phone having multiple transmitting frequency bands includes a phase detector (21) for generating a phase detector output signal in response to a phase difference between an input signal and a mixing product signal, multiple switchable voltage controlled oscillators (35, 37; 100, 101, 102; 111, 112; 120), each connected to the phase detector (21) and each generating an output oscillating signal, the frequency of which depends on the phase detector output signal, and a coupling device (44; 110; 119; 121) for coupling the output oscillating signal to a mixer (26) for mixing said output oscillating signal with a locally generated oscillating signal to produce the mixing product signal.

Abstract: A pin layout which prevents degradation of a frequency characteristic of a low noise amplifier and a receiving mixer included in a semiconductor integrated circuit for dual-band transmission/reception wherein the circuit of the low noise amplifier is provided at a position where the distance from a end of the pin outside the package of the low noise amplifier to the pad is the shortest; ground pins of two low noise amplifiers and the high frequency signal pins are arranged respectively so as not to be adjacent to each other; the power source and ground pin of the low noise amplifier, and the power source and ground pin of the bias circuit are respectively separated; and high frequency signal wires do not intersect each other.

Abstract: An AM radio receiver of a double superheterodyne type. Where a first intermediate frequency is selected to be a low frequency of several kHz other than 0 kHz. A second intermediate frequency is selected to be several tens of kHz. A first local oscillator circuit formed of a PLL generates first local oscillation signals of two kinds whose phases are different from each other by 90.degree.. First and second mixer circuits are respectively supplied with the first local oscillation signals of two kinds and mix them with a received signals to generate the first intermediate frequency. First and second filters obtain signals each having the first intermediate frequency. A second local oscillator circuit generates second local oscillation signals of two kinds whose phases are different from each other by 90.degree.. Third and fourth mixer circuits are respectively supplied with the signals having the first intermediate frequency and mix them with the second local oscillation signals.

Abstract: An ultra-widebandwidth compressive receiver includes a power divider for processing a composite input signal consisting of individual input signals. The power divider provides a plurality of power divided signals to corresponding nondispersive delay lines. Each nondispersive delay line generates a unique time delay for each power divided composite signal. The unique time delay is generated in accordance with an arithmetic progression. The unique time delay has the effect of altering the phase of a corresponding individual input signal. The time delayed composite signals are provided to a frequency converter which heterodyne mixes them with local oscillator signals of frequencies which are a base frequency plus multiples of a reference signal frequency. The result is provided to a power combiner which re-combines the time delayed and frequency converted individual input signals in order to generate a group of narrow signal pulses that are separated in time according to their frequency.

Abstract: A broadband receiver for converting an input radio frequency signal into output pulses includes provision for expanding the width of the output pulses (50) to permit pulse processing by conventional equipment at slower processing rates. A scanning local oscillator (42) frequency modulates the input signal to create a frequency modulated signal which is compressed into a pulse by a dispersive delay line (40). The width of the output pulse is increased by producing a mismatch or differential in the frequency versus time slopes (52, 54) of the oscillator and dispersive delay line. The slope differential is achieved by a function generator (58, 68) which maintains the frequency versus time slope of the scanning local oscillator at a value different than that produced by the dispersive delay line.

Abstract: A fully digitally-controlled system is disclosed which employs synthesized communications receivers to measure received signal frequency with greater resolution than that provided by the receiver alone. Variable frequency I.F. translation is used to provide this fine resolution. The operator has only one set of controls and one set of displays, with all other operations of the system being taken care of automatically without operator intervention. Proper performance of the associated one or two synthesized communications receivers is assured by continuous monitoring and display of the status of these receivers. In addition, the system may be remotely controlled; that is, it may report current frequency/bandwidth/mode settings to an external processor or it may receive commands from an external processor.

Abstract: A frequency-modulated ultrashort-wave signal is received, but due to wave-reflection phenomena from physical bodies reflecting towards the receiving antenna is amplitude modulated, this amplitude modulation being dependent upon frequency. Derived from the frequency-modulated signal is a frequency-deviation signal indicating its instantaneous frequency deviation, and also an amplitude-indicating signal indicating its instantaneous amplitude. These can be fed to the x- and y-inputs of an oscilloscope for display of an amplitude versus frequency curve used to generate a quantitative characterization of reception quality, the oscilloscope screen being provided with a horizontal reference axis.