Abstract: A signal having one of a plurality of modulation formats is formed by encoding first data in accordance with a particular one of the modulation formats. The encoded first data is then combined with second data identifying the particular modulation format of the encoded first data to form the signal.

Abstract: The invention is a radio transmitter and a method for transforming digital amplitude as well as phase or frequency modulation information into analog signals for controlling analog amplifier circuitry. The method includes providing first and second digital signals representing phase angle; converting the signals into analog signals; mixing the analog signals with oscillator signals to obtain an analog, modulated signal; providing a third digital signal corresponding to amplitude; converting this signal into an analog signal; and feeding the analog, modulated signal and said analog signal to the analog amplifier circuitry.

Abstract: A system for using a translation loop upconverter and power amplifier including a secondary phase-error correction loop uses the output of the upconverter to lock a feedback loop during a time in which the output of the power amplifier is insufficient to provide feedback to the upconverter. After the power amplifier has developed sufficient power to provide feedback to the upconverter, the feedback to the upconverter is taken from the output of the power amplifier. By placing a phase detector and phase shifter in the secondary feedback path taken from the output of the power amplifier, any phase distortion present in the system can be detected and corrected.

Abstract: Channel estimation is performed for a received signal, wherein different parts of the received signals are modulated using different modulation types. The channel is first estimated based on part of a received signal modulated with a first modulation type. This channel estimate is then transformed into a channel estimate corresponding to at least a second modulation type.

Abstract: An inexpensive method and means for generating high power envelope-modulated radio frequency signals is disclosed. Embodiments provide EER amplification and separate modulation of information encoded as phase angle and as amplitude. An envelope modulated signal generation apparatus comprising a source of carrier signal, a source of a binary data stream, a pulse deletion logic and a current switch is disclosed.

Abstract: The modulator has an input (30) which receives data to be modulated. A plurality of memory regions acting as look-up tables (38-44) are arranged to contain information relating to the modulation method to be carried out by the modulator. At least one of the memory regions provides time independent modulation values and at least one of the memory regions provides time dependent modulation values. Values provided by the memory region is dependent on the data received via the input. Processing means provide a modulating signal based on the values provided by the memory regions.

Abstract: The present invention, according to one embodiment, relates to a method for matching the dynamic range of an information signal to the dynamic range of a receptor. The method comprises the steps of: monitoring the information signal; varying the gain of the information signal in response to the monitoring step so as to provide a gain adjusted information signal; generating a variable control signal having a frequency outside frequency range of the information signal, in response to the monitoring step; combining the control signal with the gain adjusted information signal so as to provide a combined information signal; and providing a variable amplitude dependent gain to the combined information signal so as to provide an output signal that substantially matches the dynamic range of the receptor.

Abstract: A modulator and a method of modulating utilizes phase or frequency modulation and amplitude modulation. A delay circuit or synchronization circuit is utilized to coordinate the performance of amplitude modulation and phase modulation. The amplitude modulation can be provided after phase modulation is provided to the signal. The modulation circuit can be utilized in any frequency range including high frequency and low frequency circuits.

Abstract: The proposed phase lock technique uses various feedback loops to lock the frequency and phase of a CATV modulator output signal to that of an off-air signal without directly measuring the output frequency. One embodiment includes a tuner for receiving the off-air signal and generating an intermediate frequency signal and a phase-frequency detector for comparing the frequency and phase of the intermediate frequency signal generated by the tuner with the frequency and phase of an intermediate frequency signal generated by the modulator based on a reference input signal. The output of the phase-frequency detector is used to control the reference input signal into the modulator and the reference input signal to the tuner such that the frequency and phase of the modulator output signal is locked to the frequency and phase of the received off-air signal.

Abstract: A novel communications method for generating specific unique information containing waveforms, for geometrically modulating a signal with those waveforms, and an apparatus for generating the waveforms, geometrically modulating carrier waves with those waveforms, or broadcasting the novel waves by RF, microwave, electric cable, or fiberoptic conduits.

Abstract: It is to provide a multi-signal generator which is able to lower the cost thereof by performing modulation in a low frequency range and using an output of a frequency synthesizer commonly to all channels. The multi-signal generator for generating a multi-signal which is a combination of a plurality of output signals generated by a plurality of channels each of which is using a frequency conversion method wherein a modulated carrier signal and a local signal are frequency converted by a mixer, wherein an output frequency from at least one frequency synthesizer is commonly used as a frequency source for the carrier signal or local signal by all the channels.

Abstract: An apparatus and method generate a linearly modulated signal in a polar modulation system. A signal for transmission is separated into a phase component and an amplitude component, and a carrier signal is modulated with the phase component in a phase modulator, creating a phase distortion. A compensator compensates for the phase distortion created by the phase modulator by modifying the amplitude component. The phase modulated carrier signal is amplitude modulated by the compensated amplitude component to produce a linearly modulated signal.

Abstract: A transmitter and a phase locked loop (30) for a transmitter are disclosed. The phase locked loop (30) upconverts the frequency of a baseband signal to a frequency for radio transmission. As well as the usual components, the phase locked loop (30) comprises a modulator (39) for modulating a baseband signal (f.sub.bb) onto a carrier (f.sub.ref /R) and forwarding the resultant modulated signal (f.sub.c) to one of the inputs of the phase detector (33). It also comprises a low pass filter (38) in its forward path between the phase detector (33) and the voltage controlled oscillator (34) for passing signals having baseband signal frequencies. A mixer (35) and main frequency divider (36) are provided in the feedback path to downconvert the transmit signal (f.sub.tx). This low division eliminates large amounts of multiplicative noise within the loop bandwidth, and therefore enables a large loop bandwidth to be used. Consequently, the settling time of the phase locked loop is improved.

Abstract: In a radio communication system (100), enhanced communication capability is provided while maintaining standard channel modulation compatibility. At a transmitter (110, 200, 600), a first information signal is generated from data according to a predefined standard modulation scheme (212, 613). A second information signal is generated from data that provides supplemental information to the standard modulated data (213, 616). For transmission, the first and second information signals are combined into a composite signal (214, 619) that represents the first information signal when interpreted according to the predefined standard modulation scheme.

Abstract: A digital modulation technique, broadcast system, and apparatus for the spectral superposition of an analog AM signal and a novel digitally modulated signal. Multiple mutually orthogonal, continuous-valued noise-like sequences are amplitude and phase modulated. Preferably, modulation coefficients are mapped from the formatted data to be transmitted and basis waveforms are generated which are then modulated by the modulation coefficients. These modulated waveforms may be ASK modulated lowpass waveforms and QAM or in-phase ASK modulated bandpass waveforms. Alternatively, the modulated waveforms may be double sideband QAM modulated lowpass waveforms and QAM modulated bandpass waveforms. In the broadcast system of the present invention, an amplitude modulated signal having a first frequency spectrum is broadcast simultaneously with a plurality of amplitude and/or phase modulated orthogonal noise-like signals having a bandwidth which encompasses the first frequency spectrum.

Abstract: An apparatus and method for generating a broadcast waveform is provided which, for generating an in-phase component, includes an in-phase digital signal generator; a first filter for filtering the in-phase digital signal; a first digital-to-analog converter for converting the filtered digital signal into a first analog signal; an AM baseband signal generator producing an AM baseband signal; a first summer for summing the first analog and AM baseband signals to produce a composite analog signal; and a first modulator for modulating the composite analog signal with a first carrier signal at a transmission frequency, thus producing a first modulated signal.

Abstract: A novel communications method for generating specific unique information containing waveforms, for geometrically modulating a signal with those waveforms, and an apparatus for generating the waveforms, geometrically modulating carrier waves with those waveforms, or broadcasting the novel waves by RF, microwave, electric cable, or fiberoptic conduits.

Abstract: A digital and analog modulator is configured in a simplified circuit structure. The modulator includes a first frequency mixer circuit for modulating a carrier with an analog signal or a sine wave component of a digital signal, a second frequency mixer circuit for modulating a signal attained by shifting a phase of the carrier with an analog signal or a cosine wave component of the digital signal, and an adder for adding signals from the first and second frequency mixer circuits to each other.

Abstract: The method for generating a modulated television signal involves performing a first filtering and a second filtering to obtain two signals, one having a passband that is equal to complete passband and the other one having a passband that is equal to the sideband to be suppressed. The signal having a complete passband is amplitude-modulated with a video carrier, obtaining a first signal. The signal having a passband equal to the sideband to be suppressed is then divided into a first component and a second component, and the first component is phase-shifting by 90.degree. with respect to the second component. The first component is modulated with a video carrier that is phase shifted by 90.degree., obtaining a second signal. The second component of the signal having a passband equal to the sideband to be suppressed is modulated with the video carrier, obtaining a third signal. The second and third signals are then subjected to an algebraic sum, obtaining a fourth signal.

Abstract: A system and method is disclosed that provides a means for the high efficiency low distortion amplification of complex modulated radio frequency signals, such as but not limited to Single Side Band (SSB) signals. The innovative principle of the invention is based on the simultaneous amplitude and phase or angle modulation of Class "C" amplifier. Complex signals such as SSB signals can be described as a combination of amplitude and phase or angle modulation. By determining the amplitude and phase or angle components of the complex signal and using these to modulate a Class "C" amplifier, according to the manner prescribed in the invention, the objective of high efficiency low distortion is achieved. Previously, Class "B" amplifiers were required to amplify complex RF signals. The maximum efficiency of a Class "B" amplifier typically achieved in practice is about 40 percent compared to about 85 percent for Class "C" amplifiers.

Abstract: An IQ modulator incorporates a quadrature network that is responsive to a frequency dependent control signal and that has in-phase and quadrature signals that are of equal amplitude and in exact quadrature over a wide range of applied frequencies. The quadrature network includes RC and CR phase shifters whose C's are fixed capacitors of equal value and whose R's are made equal to each other and to the capacitive reactance of the C's by the action of the frequency dependent control signal. The R's may be FET's. The frequency dependent control signal may be generated without express knowledge of the applied frequency by a servo loop that nulls out the amplitude difference between the in-phase and quadrature outputs from the quadrature network; it may also be generated from a look-up table as an express function of frequency. The frequency dependent control signal is split into separate instances that are applied to each R, and an offset may be introduced therebetween to provide extreme precision.

Abstract: A radio-frequency broadcasting system and method for simultaneously broadcasting analog and digital signals in a standard AM broadcasting channel wherein the system includes: a transmitter for providing, and broadcasting, a composite signal containing an adaptively-modulated phase-shift-keyed digital signal with analog programming material modulated thereon; and a receiver for detecting the composite signal, extracting the analog audio signal and digital audio, or data, therefrom, and playing back the received audio programming. The adaptively-modulated phase-shift-keyed digital signal is responsive to the transmitted signal, dynamically increasing the digital data transmission rate as the transmitted signal power increases. Symbol states are generally arranged around concentric arcs, and adjacent symbol states are generally equidistant.

Abstract: A method and apparatus for generating an amplitude-modulated signal based on a modulation signal including first and second digital oscillators which are controlled based on first and second phase shifts derived from the modulation signal, and output first and second phase-modulated signals having a same amplitude and first and second phases, respectively; first and second amplification channels which amplify the first and second phase-modulated signals, respectively, and output first and second amplified phase-modulated signals; an adder which adds the first and second amplified phase-modulated signals and outputs a resultant amplitude-modulated signal; and a filter which filters the resultant amplitude-modulated signal and outputs the amplitude-modulated signal. The method and apparatus for amplitude modulation is suited for applications in "solid state" power transmitters.

Abstract: A multiple-modulation communication system includes a transmitter that modulates and transmits communication signals modulated by a first modulation technique and communication signals modulated by a second modulation technique. The first modulation technique and the second modulation technique are different. The communication system also includes a receiver capable of receiving the communication signals modulated by the first modulation technique and the communication signals modulated by the second modulation technique and demodulating the communication signals.

Abstract: Device and process for the generation of amplitude-modulated radiofrequency excitation pulses. A first unit (2) delivers a radiofrequency signal of constant level and a second unit (3) delivers a modulation signal of the radiofrequency signal, formed from numerical data. At least two analog multipliers (6) are connected in cascade as to the radiofrequency signal (RF) from the first unit (2) and are supplied in parallel by the modulation signal (SM) from the second unit (3). For n multipliers (6) in cascade, with n.gtoreq.2, the modulation signal (SM) delivered to the n multipliers (6) is of the A.sup.1/n.f(t) type, A.f(t) being the desired resulting modulation signal (SMR). The second unit (3) is a memory (4) containing point by point the envelope of the modulation signal A.sup.1/n.f(t) and a digital/analog converter (5) whose output is connected to the inputs in parallel of the n analog multipliers (6) in cascade.

Abstract: A novel communications method for generating specific unique information containing waveforms, for geometrically modulating a signal with those waveforms, and an apparatus for generating the waveforms, geometrically modulating carrier waves with those waveforms, or broadcasting the novel waves by RF, microwave, electric cable, or fiberoptic conduits.

Abstract: In an amplitude modulator, a delta sigma modulator converts a digital or analog modulation signal into a binary signal. The binary signal and a carrier signal are sent to a multiplication circuit. The phase of the carrier signal is changed to normal phase or opposite phase. The resultant carrier signal is output as an amplitude modulation wave. An orthogonal modulator sends a local oscillation signal to a phase shifter. The phase shifter outputs two carrier signals with phases which differ by 90.degree. each other. The modulation signal and carrier signals are sent to the amplitude modulator. The amplitude modulator outputs an amplitude modulation signal. These signals are sent to an analog signal composing unit. The analog signal composing unit composes the input signals and outputs an amplitude and phase modulation signal.

Abstract: A modulation apparatus for a cellular radio system in which capacity is increased and power consumption is minimized, said system covering large and small area cells of different sizes. At least two different modulation schemes are used in the system. For large area cells, constant envelope modulation is used for minimizing power consumption, and for small area cells, linear modulation is used for minimizing the channel spacing, and in this manner, for increasing the cellular capacity.

Abstract: The present invention provides a system and method in which an arbitrary information-modulated signal is efficiently amplified to high power levels. The arbitrary information-modulated signal is received at a low power level and is separated into elemental signals. In a preferred embodiment, a frequency/phase information signal and an amplitude information signal are the elemental signals which collectively represent the essential information in the original information-modulated signal. The circuit uses the elemental signals to provide an amplified replica of the original information-modulated signal. The amplification preferably, though not necessarily, involves using the digital amplitude modulators disclosed in U.S. Pat. No. 4,804,931, U.S. Pat. No. 5,260,674, or U.S. Pat. No. 5,367,272.

Abstract: A wide-band microwave modulator arrangement for an information transmission system, such as a video signal distribution system, in which signals from a microwave carrier signal source are split and directed over a first path comprising an attenuator and a second path comprising phase shift means and a balanced modulator, the output signals from the two paths being combined for transmission. Signals from the carrier signal source may also be directed over a third path including phase shift means and a second balanced modulator, amplified output signals from the first two paths being combined with output signals from this third path before transmission.

Abstract: A novel communication apparatus comprising a transmitter capable of geometrically modulating an existing modulated electromagnetic signal, a method for geometrically modulating a frequency modulated signal, and a receiver for decoding the modulated signal waveform without damaging the underlying harmonic content of the carrier wave and decoding the underlying modulated electromagnetic signal.

Abstract: In an amplitude-modulated broadcast transmitter for various types of modulation, particularly DSB (double sideband), SSB (single sideband) and ISB (independent sideband), of at least one AF signal to be transmitted, the sum and the difference is formed from the two input channels (7a, 7b). Either the sum or the difference is subjected to a Hilbert transformation in a Hilbert transformer (12). From these signals, an amplitude signal is formed in an amplitude processor (22) and a phase signal is formed in a cyclic sampler (21) and a phase conditioner (23). The amplitude signal is used for anode modulating the transmitting tube (5) and the phase signal is used for grid modulating the transmitting tube. The amplitude-modulated broadcast transmitter for various types of modulation has the advantage that the three types of modulation ISB, DSB and SSB can be set by allocating the AF signals to be transmitted to the two input channels (7a, 7b).

Abstract: A method for simultaneously imposing a single modulating signal on a number of constant frequency carriers includes applying the single modulating signal and all of the carriers to a doubly-balanced mixer circuit that produces sideband signals that are uncontaminated by the carriers. The sideband signals thus produced are then combined with signals proportional to the carriers in a linear circuit to obtain an output signal equivalent to a signal that would result from combining separately modulated carriers.

Abstract: Transmitting signals containing amplitude modulated (AM) and phase modulation (PM) components requires a transmitter having AM and PM control loops. The PM control loop provides phase modulation, frequency translation and phase predistortion for the transmitter. The phase predistortion/correction is accomplished by using an oscillator, thus, the amount of PA phase correction is essentially unlimited. Additionally, the PM control loop is nested about a power amplifier (PA), allowing the PM control loop to correct for any distortion introduced by the PA.

Abstract: The process according to the invention consists in breaking down a radiofrequency signal to be modulated according to a first and second signal, representing respectively the sum of the output voltages of identical amplitude of a first and second determined number of modules, with which respectively a first and second vector are associated whose respective amplitude and phase verify that the vectorial sum of the two vectors coincides with a determined reference that is used as a phase reference of the two vectors, in adapting the phase of the load impedance of each module so that vector associated with the current supplied by each of the amplifying modules is in phase delay in relation to their output voltages, in modulating the phase of the two signals by the modulation signal and in adding the first and second phase modulated signal to obtain a resultant amplitude modulated signal. Application: Medium wave radio broadcast transmitters.

Abstract: Apparatus and method for effecting single sideband suppressed carrier modulation suitable for small, hand-held, high-frequency cellular radio transmitters such as those used at 900 mHz. A local oscillator generates a signal at 0.8 the frequency of the desired carrier. The generated frequency is counted down to produce an IF that is 0.2 the frequency of the desired carrier and the IF is mixed with the baseband signal to produce a modulated IF. The modulated IF is then mixed with the first generated signal to generate the modulated carrier signal. Advantageously, all of the foregoing components can be provided on the same integrated circuit chip.

Abstract: A numerically-controlled modulated oscillator and modulation method which selectively provides frequency modulation, phase modulation or amplitude modulation with minimal circuitry. A numerically-controlled modulated oscillator is provided having a tuning register for receiving a center frequency parameter, an adder for receiving at one input the frequency parameter, a phase accumulator for receiving a phase increment number from the adder and producing a waveform phase number, a waveform memory for producing a waveform amplitude number in response to the phase number, and a digital-to-analog converter for producing an analog signal in response to the waveform amplitude number. Another input is provided to the adder from an angle modulation register which provides an angle modulation parameter. This parameter can perform either phase or frequency modulation.

Abstract: A digital amplitude modulator receives a plurality of phase coherent input signals from a plurality of amplifiers (A1-An) respectively representing the bits of a plural bit digital word and converts them to a single output signal on an output with a first plurality of transformers having transformer ratios which vary substantially in accordance with a power of two corresponding to the significance of the bit represented by the input signal being converted thereby and a second plurality of transformers having primaries connected to the first plurality of transformers, respectively, and secondaries all connected in series together to an output terminal and transformer ratios which vary in substantial accordance with the same powers of two that the transformer ratio of the first plurality of transformers to which they are connected vary.

Abstract: In a vestigial sideband modulator, an i.f. signal is modulated with a video input and the extreme part of one of the sidebands is removed to provide the right frequency response shape for transmission. The signal for transmission is usually produced by mixing the i.f. signal with an oscillator signal known as the heterodyne signal which differs from the desired carrier frequency by the i.f. frequency, and filtering the signal with a subsequent channel filter to remove any unwanted heterodyne oscillator components and the unwanted sum or difference product. To avoid the need for such a channel filter, the filtered video-modulated i.f. signal is demodulated to quadrature baseband components using the i.f. oscillator, and quadrature components at carrier frequency are modulated with these baseband components to produce on combination a v.s.b. modulated video output at carrier frequency.

Abstract: A method and apparatus for generation of high frequency pulses and for excitation of nuclear magnetic resonance of a sample generates a plurality of modurated high frequency waves having different frequencies from each other, and combines the generated these high frequency waves so as to generate high frequency pulses which provide a frequency spectrum having a predetermined band, thereby a shortening of the high frequency pulse width as well as a narrowing of the frequency band is achieved.

Abstract: A new method of modulating and demodulating signals and circuitry therefor is disclosed. The modulation circuit defines a non-linear voltage current transfer function wherein at low voltage levels the current voltage transfer function is substantially linear and at higher voltages, the transfer function is substantially exponential. The modulation circuit can be designed of three parallel branches, a resistive branch, and two diodes in the remaining branches, the anode of one diode being coupled to the cathode of the other diode. Demodulation circuitry is also disclosed that includes a circuit for determining the instantaneous phase and amplitude and then processing circuitry to decode the modulation information based upon the sampled phase and amplitude data.

Abstract: An amplitude modulated RF amplifier using dual path modulation to increase operating efficiency. Both the RF drive to the amplifier and the DC power supply voltage to the amplifier are amplitude modulated. Preferably, the power supply modulation is accomplished with a high efficiency pulse width modulator circuit. To prevent phase shift distortion, the modulated DC output from the power supply is used both to power the RF amplifier and to amplitude modulate the RF drive to the amplifier. For maximum efficiency, the modulators are both non-linear. Maximum efficiency is realized with primarily supply modulation and some drive modulation providing the positive envelope modulation and primarily a non-linear RF drive modulation providing the negative envelope modulation. The use of primarily RF drive modulation for the deep negative modulation will reduce the amount of incidental phase modulation experienced, while having a nearly inconsequential effect on total efficiency of the RF amplifier.

Abstract: A vector locked loop is disclosed having a topology somewhat similar to two cross coupled phase locked loops, but wherein both magnitude and phase are used as feedback signals. The output signal is generated by combining the outputs of two VCOs in a combiner network. This output signal is fed back to the input, where phase and magnitude detectors are used to generate error signals. These error signals are processed to yield control signals for controlling the frequencies of the two VCOs. The vector locked loop can be adapted for a number of applications, including frequency translation, modulation (phase, amplitude or arbitrary), and high efficiency linear power amplification.

Abstract: Vector modulation is effected by summing output signals from two phase modulators. The lack of amplitude modulation on the signals when summed permits non-linear processing of the signals, such as PLL frequency translation. In one embodiment, the phase modulators comprise fractional-N phase locked loops modulated with digital data words. In another, the phase modulators comprise direct digital synthesizers.

Abstract: A system of transmission with amplitude modulation for the transmission of signals of all types, analog and/or digital, requiring high performance characteristics with respect to the noise induced by the transmission channel, comprising, at transmission, means for the suppressed carrier amplitude modulation of a useful signal and means for the amplitude modulation, in phase quadrature with said modulated useful signal, of a service signal, making it possible, at reception, to remove the ambiguity on the polarity of the demodulated useful signal. Thus it enables the transmission of signals in suppressed carrier modulation mode, hence with a good signal-to-noise ratio, without losing the polarity of the signal. The transmitters and receivers according to the invention also enable the transmission and reception of the signals modulated in SCAM, VSBAM or VSBSCAM modes.

Abstract: A digital amplitude modulation apparatus for amplitude-modulating a digital carrier having a frequency fc by a digital modulating wave associated with a sampling frequency fs1, at a sampling frequency fs2, wherein the conditions m.times.fs1=fs2, and fc=n/4.times. fs2 are satisfied, where m is a positive integer (2, 4, 6, . . . ) and n is a positive integer (1, 3, 5, . . . ). A fold distortion relative to an original digital amplitude modulated wave is not generated even if a fold component elimination filter is not used.

Abstract: An RF power supply serves to supply a regulated power amplified RF drive signal to an RF transmitter. The supply includes an RF oscillator for providing an RF input signal. A DC voltage source provides a DC voltage V. A plurality of power amplifiers are provided with each receiving the input RF signal and each having an input for receiving a DC voltage signal, and each serving to amplify the input RF signal by an amount dependent upon the magnitude of the DC voltage signal supplied to its input and thereby provide an amplified RF signal. The amplified RF signals are combined to provide an RF drive signal. The DC voltage V is directly supplied to the input of at least a first one of the power amplifiers.