Abstract: A multiband and multimode transmitter circuit (200) includes two separate oscillators, such as at least a first oscillator circuit (60), a second oscillator circuit (62), a corresponding first signal processing circuit (64), and second signal processing circuit (66) to produce a first output frequency signal (78) defined within the first or second band of frequencies in response to a transmitter input signal (46). Each oscillator and corresponding signal processing circuit (64, 66) may be optimized for the lowest power consumption while meeting the noise performance criteria in each of the multiple frequency bands. The multiband and multimode transmitter circuit (200) may produce the transmitter output signal (36) with either linear modulation or nonlinear modulation and at a first band or second band frequencies.

Abstract: Quadrature demodulator and quadrature modulator which comprise a first oscillator and a second oscillator, a separate excitation signal being fed to the first and second oscillator to determine the time at which switching between two stable states takes place, and the quadrature demodulator and quadrature modulator further comprise excitation elements In the quadrature demodulator, an input signal is fed, which influences a parameter of one of the elements of the first and the second oscillator and produces a set of quadrature output signals. In the quadrature modulator, a first and second quadrature signals are fed to the quadrature modulator, which influences a parameter of one of the elements of the first and the second oscillator, and the quadrature modulator further comprises summing elements to produce a modulated output signal.

Abstract: In the synthesis of frequency channel spacing in an RF transmission signal, a raster component of the desired frequency channel spacing is provided by an integer IF frequency synthesizer (44). Because the frequencies associated with the IF synthesizer are lower then those associated with an RF frequency synthesizer (48), the IF synthesizer can incorporate the desired raster using a lower feedback divisor (N) than can the RF synthesizer.

Abstract: An apparatus for generating a modulated signal which includes a modulator operative for receiving a first signal and input data signals, and modulating the first signal in accordance with the input data signals so as to produce a modulated reference signal; a first frequency divider coupled to the modulator output, operative to reduce the frequency of the modulated reference signal by a predetermined factor; a signal generator operative to produce a second signal; a first mixer having a first input coupled to an output of the first frequency divider and a second input coupled to the output of the signal generator. The first mixer operates to frequency translate the modulated reference signal by an amount equal to the frequency of the second signal. In addition, the signal generator of the present invention contains a direct digital synthesizer coupled to a second phase lock loop which operates to up-convert the output signal of the DDS to the microwave region.

Abstract: A waveform reconstruction circuit receives an rf signal from an antenna, digitizes it, and then generates an undistorted reconstructed waveform. The reconstructed waveform can then be conventionally mixed and demodulated to extract useful signal information with enhanced receiver fidelity and sensitivity.

Abstract: Systems and methods are provided for calibration of a transmitter system modulator, wherein local oscillator nodes of a mixer are held at first and second voltages, and a first offset value is determined. The terminals are then held at third and fourth voltages and a second offset value is determined. The first and second offset values are then averaged to provide a calibration offset value for the modulator.

Abstract: A high-speed power-efficient coded M-ary Frequency-Shift Keying (M-ary FSK) modulator. The modulator includes a coding logic, which generates (M/2) Gray code signals in accordance with an (N−1) bits control signal; and (M/2) switching oscillators. Each switching oscillator includes: a composite crystal resonator with a first end and a second end; a first switch, which is controlled by Gray code signals, with one end connected to the first end of the composite crystal resonator, and the other end grounded via an equivalent negative resistance circuit; a second switch, which is controlled by serial data, with one end connected to the second end of the composite crystal resonator, and the other end grounded; and a capacitor, with one end connected to the second end of the composite crystal resonator, and the other end grounded.

Abstract: The invention reduces transient peaks in signals transmitted in CDMA communication systems. A plurality of spread spectrum data signals are combined into a combined signal having fluctuating power level corresponding to the combination of the data signals. The combined signal is modulated to produce an RF signal for transmission. The average power of the combined signal is measured over a selected time period. The combined signal power level is adaptively limited to a calculated power level based at least in part on the measured power.

Abstract: A frequency spectrum measurement apparatus sweeps a desired frequency range using multiple scan lines. A controller provides a non-contiguous sequence of input values to a frequency synthesizer operating as a local oscillator for generating a non-contiguous frequency output signal over the desired frequency range with each value offsetting a current frequency output signal from a previous frequency output signal. A mixer receives an input signal and the variable frequency synthesizer signal for generating an intermediate frequency signal that is filtered through a bandpass filter. The power of the intermediate frequency signal output of the bandpass filter is measured and displayed. The frequency spectrum measurement apparatus is usable in measuring out of channel emissions of a terrestrial RF broadcast digital television signal.

Abstract: A digital signal processor generates in-phase, quadrature-phase and amplitude signals from a baseband signal. A modulator modulates the in-phase and quadrature-phase signals to produce a modulated signal. A phase locked loop is responsive to the modulated signal. The phase locked loop includes a controlled oscillator having a controlled oscillator input. An amplifier includes a signal input, amplitude control input and an output. The signal input is responsive to the controlled oscillator output and the amplitude control input is responsive to the amplitude signal. The phase locked loop that is responsive to the modulated signal includes a controlled oscillator output and a feedback loop between the controlled oscillator input and the controlled oscillator output. The feedback loop includes a mixer that is responsive to a local oscillator. The modulator may be placed in the phase locked loop.

Abstract: A high-speed power-efficient coded M-ary Frequency-Shift Keying (M-ary FSK) modulator. The modulator includes a coding logic, which generates (M/2) Gray code signals in accordance with an (N−1) bits control signal; and (M/2) switching oscillators. Each switching oscillator includes: a composite crystal resonator with a first end and a second end; a first switch, which is controlled by Gray code signals, with one end connected to the first end of the composite crystal resonator, and the other end grounded via an equivalent negative resistance circuit; a second switch, which is controlled by serial data, with one end connected to the second end of the composite crystal resonator, and the other end grounded; and a capacitor, with one end connected to the second end of the composite crystal resonator, and the other end grounded.

Abstract: A VSAT system for generating and transmitting a modulated data signal to a satellite. The VSAT system includes an indoor unit for generating a modulated data signal having an envelope of constant amplitude, and an outdoor unit including a transmitter module operative to receive the modulated data signal and to frequency multiply and amplify the modulated data signal so as to produce a modulated carrier signal having an envelope of constant amplitude. The transmitter module includes a multiplier operative to frequency multiply the modulated data signal to the frequency of the modulated carrier signal, and a power amplifier operated in the saturation mode, which amplifies the modulated carrier signal to the desired power level. The components constituting the transmitter module are formed on a single integrated circuit.

Abstract: An apparatus for generating a modulated signal which includes a modulator operative for receiving a first signal and input data signals, and modulating the first signal in accordance with the input data signals so as to produce a modulated reference signal; a first frequency divider coupled to the modulator output, operative to reduce the frequency of the modulated reference signal by a predetermined factor; a signal generator operative to produce a second signal; a first mixer having a first input coupled to an output of the first frequency divider and a second input coupled to the output of the signal generator. The first mixer operates to frequency translate the modulated reference signal by an amount equal to the frequency of the second signal. In addition, the signal generator of the present invention contains a direct digital synthesizer coupled to a second phase lock loop which operates to up-convert the output signal of the DDS to the microwave region.

Abstract: The present invention teaches a system for selectably oscillating at a first or a second oscillating frequency. The system comprises an oscillator for providing an oscillating output. Moreover, the system comprises a switching device for selecting a first or a second impedance in response to a select signal having a voltage. Each of the first and second impedances are fixed independently of the select signal voltage such that the oscillating output oscillates at the first oscillating frequency when the first impedance is provided and oscillates at the second oscillating frequency when the second impedance is provided.

Abstract: The present invention teaches a system for selectably oscillating at a first or a second oscillating frequency. The system comprises an oscillator for providing an oscillating output. Moreover, the system comprises a switching device for selecting a first or a second impedance in response to a select signal having a voltage. Each of the first and second impedances are fixed independently of the select signal voltage such that the oscillating output oscillates at the first oscillating frequency when the first impedance is provided and oscillates at the second oscillating frequency when the second impedance is provided.

Abstract: A waveform reconstruction circuit receives an rf signal from an antenna, digitizes it, and then generates an undistorted reconstructed waveform. The reconstructed waveform can then be conventionally mixed and demodulated to extract useful signal information with enhanced receiver fidelity and sensitivity.

Abstract: The present invention teaches a system for selectably oscillating at a first or a second oscillating frequency. The system comprises an oscillator for providing an oscillating output. Moreover, the system comprises a switching device for selecting a first or a second impedance in response to a select signal having a voltage. Each of the first and second impedances is fixed independently of the select signal voltage such that the oscillating output oscillates at the first oscillating frequency when the first impedance is provided and oscillates at the second oscillating frequency when the second impedance is provided.

Abstract: A frequency generating circuit scales a warp range of a frequency signal. The frequency generating circuit includes a first frequency signal (10) having a first offset signal with a first frequency relationship to the first frequency signal, and a second frequency signal (14). A frequency scaling element (16) receives the first frequency signal (10) and second frequency signal and provides a third frequency signal, such that the third frequency signal includes the first offset signal having a second frequency relationship to the third signal. A switch (54), has a control input (74), a first input for receiving the first frequency signal, a second input operably coupled to the frequency scaling element (16, 42) for receiving the third frequency signal and an output (76) operably coupled to the first input or the second input dependent upon a control signal applied to the control input (74).

Abstract: A radio transmitter is structured to provide frequency hopping of transmitted leakage signals in addition to RF hopping of the RF output signal. A digital computer controls a digital tuner, a TLO, a FLO, and an IF unit to provide the RF hopping and to provide digital-tuner frequency hopping and IF hopping thereby enabling the frequency hopping of transmitted leakage digital tuner and IF signals.

Abstract: A device and method for automatically controlling transmission power of a CDMA site, by automatically controlling high frequency power of the CDMA site.

Abstract: A frequency-locked loop (100) employs a controllable oscillator (102) for generating an output signal having a frequency, optional sampler (104), coupled to oscillator (102), for sampling the frequency of the output signal, a divider (106), coupled to optional sampling circuit (104), for dividing the output signal frequency to generate a prescaled signal and a microprocessor (108), coupled between the divider 106 and oscillator (102), for comparing the prescaled signal to a reference signal and generating a control signal for correcting frequency shifts based upon the comparison. The control signal generated by microprocessor (108) is non-continuous. During that time when microprocessor (108) generates no control signals, power is removed from various frequency-locked loop circuitry.

Abstract: An electronics circuit for frequency shift keying a continuous-running caer, such as a sinewave, which allows the user to vary two closely spaced frequencies from a personal computer. The electronics circuit of the present invention comprises a microcontroller which has stored therein a lower frequency and an offset frequency. After the electronics circuit is powered up the microcontroller enters the MAIN program and generates control and address signals to effect a transfer of thirty two data bits representing the lower frequency from the microcontroller to a pair of eight bit RAMS. A programmed array logic device, which receives addresses from the microcontroller, decodes the addresses and then provides chip select and output enable signals to the RAMs to allow the thirty two data bits to be written into the RAMs with the write signal being provided by the microcontroller.

Abstract: A data transmission system includes a source of a data signal and a modulator, responsive to the data signal, producing a first modulated signal representing the data signal and a second modulated signal representing a signal 180 out-of-phase with the data signal. The first and second modulated signals are transported via a transmission channel. A first demodulator demodulates the transported first modulated signal and a second demodulator demodulates the transported second modulated signal. A subtractor, responsive to the first and second demodulators, produces a signal representative of the data signal.

Abstract: An FSK modulating apparatus includes a first phase locked loop arrangement having a first voltage controlled oscillator for generating a space frequency signal of a modulation signal and a second phase locked loop arrangement having a second voltage controlled oscillator for generating a mark frequency signal of the modulation signal. The apparatus also includes a third voltage controlled oscillator used to produce an FSK modulated output signal. After input data changes frequency to a space frequency or a mark frequency, a control voltage for the phase locked loop arrangement that is associated with the resulting frequency is routed through a low pass filter having a flat group delay characteristic to the third voltage controlled oscillator. After a set period of time has elapsed, the third voltage controlled oscillator replaces the voltage controlled oscillator of the particular phase locked loop arrangement associated with the current state of the modulator signal.