Abstract: The invention relates to a method and arrangement for modulating a signal to be transmitted, the arrangement comprising an encoder and a frequency modulator. In order to enable high rate transmission in a flexible manner in a narrow frequency band, the encoder (104) is a differential encoder and before the frequency modulator, the arrangement comprises means for multiplying the signal to be transmitted by a factor of the form &pgr;/(2m), where m is a positive integer greater than one.

Abstract: A method of and apparatus for the conversion of a frequency modulated signal to a digital output are disclosed. The output of the converter is a triangularly weighted sum of the number of zero crossings of the F.M. signal in each sub-sampling interval over a sampling interval T.

Abstract: A modulator including a noise shaper receiving the input signal and providing a signal coded over one bit, a phase loop including an adder and a shift register. The adder receives the signal coded over one bit, the output of the shift register, and a constant. The input of the shift register receives the adder output. A sinusoidal shaper is coupled to the output of the shift register to provide a signal modulated in frequency by the input signal. The present invention also relates to a modulation chain including a modulator.

Abstract: A frequency synthesizer with a digital frequency lock loop (FLL) having a fast frequency lock time uses a frequency counter circuit in the feedback loop to count the output signal frequency and produce frequency count data. A modulation control circuit provides modulation data and a corresponding modulation control signal for modulating the FLL signal source. A microprocessor processes the frequency count data along with the modulation data to provide a frequency control signal for controlling the nominal, or center, frequency of the FLL signal source. By processing these data together, thereby accounting for the amount of modulation applied to the FLL signal source, the center frequency can be maintained more consistently notwithstanding the presence of modulation within the feedback loop signal.

Abstract: The present invention relates to a modulator comprising an oscillator which has an oscillation frequency, and a mixer intended to supply a modulated signal with a given output frequency. According to the invention, the nominal oscillation frequency is N times higher than the output frequency, the modulator further including a frequency divider DIV/N intended to receive the output signal of the oscillator and to apply the carrier signal to the mixer, to produce a modulated signal with a first modulation frequency and a parasitic signal with a second modulation frequency.

Abstract: The present invention relates to a voltage-controlled quartz crystal oscillator, including an oscillation transistor, the base of which is connected to a first terminal of a quartz crystal and the emitter of which is connected, via a first capacitor, to a second terminal of the quartz crystal connected to a first supply terminal, and including an active circuit introducing a variable capacitance between the base and the emitter of the oscillation transistor, the active circuit being voltage-controlled.

Abstract: A method for simultaneously transmitting multiple bits of information through space using a time varying reference signal at a first selected fixed frequency, and a time varying synchronizing clock signal at a second selected fixed frequency establishing a clock period. The signals are combined repeatedly to obtain a multiple of additive and subtractive signals each differing from each other by an integer multiplier of the reference signal frequency. The signals are injected into an N-fold gate which is controlled by the clock signal so as to transmit N-M of the N derivative signals through the N-fold gate during each clock cycle, where 0.ltoreq.M.ltoreq.N so as to produce an N bit word signal. The N bit signal is then mixed with a radio carrier signal for transmission of the N bit signal as a parallel transmission of the N bit signal. This process is repeated continuously to produce an N-times improvement in data transmission rate over serial transmission.

Abstract: A radio frequency synthesizer receives a relatively low frequency input signal and synthesizes from it a high frequency output signal whose frequency can be programmed to change in fine steps, for use e.g. in cordless telephone. The frequency synthesizer includes three linked phase locked loops with a single side band mixer in one embodiment coupling two of the phase locked loops together. This provides an output signal free of in-band frequency spurs within the spacing of two channels. The synthesizer can be integrated in a single chip with a narrowband FM modulation circuit. In spite of using a novel synthesizer to achieve monolithic integration, the user programming interface and control value equations are the industry standard format.

Abstract: The invention provides a FM modulation system using a quadrature modulator, wherein a circuit for exclusive use in FM modulation and a change-over means can be dispensed with. In this system, modulating signals are inputted to a baseband signal processing circuit, converted into digital signals after integration, and turned into an analog signal by reading out a sine wave signal pre-stored in a sin ROM, thereby generating a baseband signal I for an equi-phase signal and a baseband signal Q for a quadrature signal. By adding together results of multiplication of the baseband signal I for the equi-phase signal and the baseband signal Q for the quadrature signal by a local signal of cosine and a sine wave signal obtained by phase shifting the local signal through 90 degrees, respectively, a quadrature modulation signal containing a FM modulated signal and the maximum frequency deviation can be generated.

Abstract: A double mode modulator, particularly, for a portable telephone, which is adapted to realize both digital and analog modulations and have a low phase noise and a reduced locking time with a device readily integrated in an integrated circuit, including: a frequency synthesizer for synthesizing a particular frequency from an external reference clock signal; a digital modulator for performing a quadrature modulation for an output signal of the frequency synthesizer; and an analog modulator for performing a frequency modulation for the output signal of the frequency synthesizer.

Abstract: An amplifier (104) for a dual band device includes multiple amplifier stages coupled between an input (103) and output (105). The amplifier stages include a first amplifier stage (200) having a first amplifier (206), a second amplifier stage (202) having a second amplifier, and a third amplifier stage (204) having a third amplifier (210). A first bypass (218) in said first amplifier stage provides a bypass for signals in a first frequency band. A second bypass (250) is provided in the third amplifier stage, the second bypass to provide for signals in a second frequency band a signal path that bypasses the third amplifier. Signals in the first and second frequency bands are amplified by the second amplifier.

Abstract: An FM transmitter includes I and Q channels, each deriving a baseband sinusoidal wave having a frequency determined by speech and/or music broadcast information amplitude and nominally having the same maximum amplitude. Each wave drives a different balanced mixer, each responsive to orthogonally phased carrier waves. Outputs of the mixers are added to derive a frequency modulated output wave. The channels, mixers, and circuitry associated with them tend to introduce unwanted components in the output wave. Offset, peak amplitude, phase and relative delay of the added mixed outputs are such that the unwanted components are substantially eliminated from the output wave. The sinusoidal waves are derived by DACs responsive to signals derived by a digital processor having a memory storing amplitude vs. phase position values and slope vs. phase position values that are combined in response to samples of the broadcast information.

Abstract: A frequency modulation circuit which generates a frequency modulation signal responsive to a video input signal includes a programmable control circuit, an electrical flow control circuit, and an oscillation circuit. The programmable control circuit generates a plurality of electrical flow control signals responsive to an electronic data input. The electrical flow control circuit controls an electrical flow therethrough responsive to the plurality of electrical flow control signals. The oscillation circuits generates the frequency modulation signal responsive to the video input signal and responsive to the electrical flow through the electrical flow control circuit. Related methods are also disclosed.

Abstract: A method for frequency modulation synthesis and apparatus for performing the method. The method uses additions rather than multiplies and therefore saves the space and cost of multipliers in circuit implementations. The method saves further resources by using the coordinate rotation digital computer (CORDIC) algorithm to acquire sine values as opposed to an extensive sine look-up table. The method can be implemented with either a dedicated digital circuit or a programmed special purpose processor such as a digital signal processor. The hardware for implementing the method is normally integrated onto a semiconductor device.

Abstract: A digital modulator capable of obtaining a high FM modulation index and reducing the quantization noise without increasing the sampling frequency of an A/D converter of input voice. A phase variation .phi.(Ts) of the digital data (Ts is the sampling period) produced on the basis of the output from the A/D converter is divided by a predetermined integer N (N>1) by a divider, and is fed to an integrator. The integrator integrates the divided phase variation .phi.(Ts)/N for every time interval Ts/N, thereby producing a phase component .phi.(t) of the complex envelope of the modulation signal. The phase component .phi.(t) is resolved into cosine and sine components at the time interval Ts/N. The cosine and sine signals are D/A converted into analog signals which are quadrature modulated by a quadrature modulator.

Abstract: Mixing, modulation and demodulation using the nonlinear properties of microelectromechanical resonators and filters are described. Mixing followed by filtering is implemented using microelectromechanical filters with nonlinear input transducers. AM modulation is implemented by passing a carrier signal through the output transducer of a microelectromechanical filter. FM and FSK demodulation is accomplished using parallel banks of microelectromechanical filters. The invention can be implemented using integrated circuit technology.

Abstract: A remote ground terminal transmitter for transmitting a modulated data signal having a constant envelope amplitude. The remote ground terminal transmitter comprises a source of data signals, a modulator for providing a carrier signal, receiving a data signal from the source of data signals, and modulating the carrier signal with the received data signal so as to produce a constant envelope minimum shift key modulation signal. The transmitter further comprises a power amplifier which operates in the saturation mode to amplify the modulated carrier signal produced by the modulator to the desired power level.

Abstract: A transformer. According to one embodiment, the planar transformer has a first winding, a first conducting surface adjacent to the first winding, a second winding and a second conducting surface adjacent to the second winding. The first conducting surface is coupled to a first ground and the second conducting surface is coupled to a second ground.

Abstract: A frequency modulator controls the center frequency and modulation factor at the same time with one control signal. The frequency modulator includes a voltage-to-current converter that receives an input voltage signal to be modulated, a reference voltage signal, and a control voltage signal, and generates an output current signal by combining the input voltage signal and the control voltage signal. The input voltage signal is amplified by a transconductance amplifier. The control voltage signal is converted into a gain signal which is used to vary the transconductance of the amplifier. A voltage controlled oscillator generates a frequency modulated signal responsive to the output current signal. The center frequency and modulation factor can be controlled by adjusting the value of a resistor in the current-to-voltage converter, a capacitor in the voltage control oscillator, or the control voltage signal.

Abstract: A digital modulator capable of obtaining a high FM modulation index and reducing the quantization noise without increasing the sampling frequency of an A/D converter of input voice. A phase variation .phi.(Ts) of the digital data (Ts is the sampling period) produced on the basis of the output from the A/D converter is divided by a predetermined integer N (N>1) by a divider, and is fed to an integrator. The integrator integrates the divided phase variation .phi.(Ts)/N for every time interval Ts/N, thereby producing a phase component .phi.(t) of the complex envelope of the modulation signal. The phase component .phi.(t) is resolved into cosine and sine components at the time interval Ts/N. The cosine and sine signals are D/A converted into analog signals which are quadrature modulated by a quadrature modulator.

Abstract: A digital system accommodates analog communications, thus avoiding the need for separate subsystems each dedicated to either analog or digital communications. The system includes a receive circuit for converting received signals into an intermediate frequency, a transmit circuit for modulating and transmitting signals and signal processors for processing the intermediate frequency signals and the signals to be transmitted, wherein the signals can be processed into digital or analog format using substantially the same circuitry.

Abstract: A high frequency arbitrarily modulated signal and noise generator utilizes digital numerically controlled oscillators providing interbusiness directly to an adder and which are phase modulated. The digital adder feeds a digital analog converter, eliminating the need for a digital multiplier while providing amplitude or phase modulation with high resolution and at high processing speeds.

Abstract: A communications reduced instruction processor forming a simple programmable digital signal processing architecture (10) for processing analog waveforms. The architecture (10) includes a main DSP core that includes a tightly coupled CORDIC co-processing element (26). The CORDIC co-processing element (26) performs trigonometric operations for converting polar coordinates to rectangular coordinates and rectangular coordinates to polar coordinates. These trigonometric functions include an angle accumulate operation for calculating the magnitude and angle of a vector given in X-Y cartesian coordinates, and a vector rotate operation for calculating a sine and a cosine of a given phase angle.

Abstract: The dual mode amplifier network of the present invention enables a radiotelephone to operate efficiently in both the U.S. Digital Cellular mode and the FM analog cellular mode. Multiple, switched branches (110 and 120) permit one branch (110) with an isolator (103) to be used in the in the U.S. Digital Cellular mode while the other branch (120) is switched out. In the analog mode, the transmit filter branch (120) is used while the isolator branch (110) is switched out.

Abstract: In a frequency modulator (1) having an adjusting circuit by which frequency modulator an applied luminance signal of a color video signal that contains synchronization pulses is frequency modulated, while the chrominance signal of the color video signal is modulated on a carrier, that has a quiescent frequency if no color information is available. A capacitor is provided for an automatic mode of operation, and is charged or discharged, respectively, in dependence on the period duration of the modulator output signal and in dependence on the period duration of the quiescent frequency of the chrominance carrier.

Abstract: A coefficient circuit 11 multiplies a digitized input modulation signal by a constant and outputs the multiplied signal. Delay circuits 12 and 13 delay the discrete in-phase input signal and discrete quadrature-phase input signal by 1 sampling cycle, respectively. A multiplying circuit 14 multiplies the multiplied signal by the 1-sampling cycle delayed discrete quadrature-phase input signal. The multiplying circuit 15 multiplies the multiplied signal by the 1-sampling cycle delayed discrete in-phase input signal. The adder circuit 16 adds the multiplication results of the multiplying circuit 14 to the 1-sampling cycle delayed discrete in-phase input signal and outputs the addition result as the discrete in-phase input signal. The subtracting circuit 17 subtracts the multiplication results of the multiplying circuit 15 from the 1-sampling cycle delayed discrete quadrature-phase input signal and outputs the subtraction result as the discrete quadrature-phase input signal.

Abstract: An integrated circuit is provided with particular application for high frequency modulation circuits, such as a mixer circuit, with reduced noise and gain. The circuit provides a novel application of a single device comprising a 4 or 5 terminal, gate controlled lateral bipolar junction transistor device, in the form of a merged MOS and lateral bipolar transistor. In a grounded base configuration, RF and LO signals are applied to the gate and emitter terminals respectively and provide for modulated output at the collector, and provides signal modulation with reduced noise compared with multi-device implementations of known mixer circuits using a summation circuit, diodes and FETs. Advantageously, operation of the device in the grounded base or grounded emitter configuration provides for strong modulation of the DC current gain, i.e. over 4 decades, as a function of gate voltage.

Abstract: Apparatus and a method for generating all of the assignable carrier frequencies in the FM broadcast band and for frequency modulating the generated carriers includes a generator of a train of pulses having a crystal-controlled repetition frequency and a specific pulse shape which together produce a spectrum of odd harmonics of the pulse repetition frequency whose separation in frequency is identical to that of the assignable carrier frequencies. This pulse train is then mixed with a 98.0 MHz sine wave to translate the spectrum to the FM band. Simultaneous modulation of all the carriers is achieved by frequency modulating the 98.0 MHz sine wave, whereby the same modulation is imparted simultaneously to all of the carriers.

Abstract: An electrical circuit comprising means for receiving an input signal for encoding or modulating and amplification. Multiple amplification stages including at least one transconductance amplifier are provided. There are means for having the input signal modulate the oscillator constituted by the multiple amplification stages to provide a 360.degree. phase-shifted signal at a predetermined frequency. Gain control means are also provided for developing level for permitting oscillation under conditions including at least the conditions of turn on of the circuit and other operating conditions. The gain control means includes a transistor and resistor network for adjusting the gain to sustain the oscillation. The transistor and resistor also regulate amplification of an intermediate stage of the amplifier. The preamplifier directly converts an EKG and/or other signals to linearized control currents which modulate the oscillator.

Abstract: An A/D converter (1) converts analog modulation signals, such as video signals and audio signals, into digital modulation signals. A center frequency data setting circuit (6) outputs center frequency data for setting the center frequency of an FM wave. An operation unit (5) outputs such addition data, on the basis of the center frequency data and average frequency data from a counter circuit (4) as will make the average frequency of the FM wave substantially identical with the center frequency that has been set. An adder (2) adds the digital modulation signals and the addition data, and outputs addition digital signals. A DDS (3) accumulates an addition digital signal in every sampling period supplied from a reference oscillator (7). In the ROM (32) of the DDS (3) are stored sine wave data and the ROM (32), having the accumulated signals as its address input, outputs the sine wave data.

Abstract: A modulation circuit utilized in a mobile radio communication transmitter includes an amplifier for amplifying a modulation signal and a modulator having a voltage-controlled oscillator for generating a frequency modulation signal corresponding to the modulation signal. An amplifier controller applies a first predetermined constant direct current voltage V.sub.1 to a power source of the amplifier when the frequency of the modulation signal is less than a predetermined frequency f.sub.3, and for a second predetermined constant direct current voltage V.sub.2 to a power source of the amplifier when the frequency of the modulation signal is higher than the frequency f.sub.3. Thus, when the frequency of the modulation signal is less than the frequency f.sub.3, the amplitude of the modulation signal which is added to the voltage-controlled oscillator decreases by a predetermined value compared with the case where the frequency of the modulation signal is higher than the frequency f.sub.3.

Abstract: A quadrature modulation circuit incorporated in a radio communication apparatus and selectively implementing transmission and reception in an analog mode or in a digital mode with a single circuitry. A VCO (Voltage Controlled Oscillator) or a frequency synthesizer including a VCO has an analog modulation capability and replaces a local oscillator included in a conventional modulator circuit for feeding an output thereof to a digital modulator.

Abstract: A digital FM modulator includes an A/D converter, a multiplier, an adder, a direct digital synthesizer, and an addition data output circuit. The A/D converter digitally encodes an input modulation signal. The multiplier multiplies an output from the A/D converter and multiplication data input from an external circuit. The adder adds output data from the multiplier to addition data. The direct digital synthesizer changes an oscillation frequency on the basis of output data from the adder with respect to a reference frequency of a reference oscillator. The addition data output circuit changes the addition data to prevent a center frequency from changing in accordance with the multiplication data and outputs the addition data.

Abstract: A radio communication apparatus used for both digital communications and analog communications is disclosed which comprises a digital signal processor DSP (4) which processes many kinds of digital signals according to a plurality of signal procedures (55,56,57,58) stored in the ROM (5). In the present invention, since the radio communication apparatus processes many kinds of procedures (55,56,57,58) stored in the ROM (5), the size of the apparatus becomes small and weight becomes light.

Abstract: A digital quadrature modulator having a first storage device for receiving an I phase component of a digital baseband signal and digital carrier phase information as a higher order address and a lower order address, respectively, and a second storage device for receiving a Q phase component of the digital baseband signal and the digital carrier phase information as a higher order address and a lower order address, respectively. The carrier phases of the carrier phase information applied to the first and the second storage devices are out of phase from each other by .pi./2. The first storage device outputs a multiplication result of the I phase component and a carrier signal and the second storage device outputs a multiplication result of the Q phase component and the carrier signal based on these addresses. These outputs are added to each other in a digital manner and then converted into an analog signal which is supplied as a modulated signal.

Abstract: A cellular-telephone transmitter (10) employs a vector modulator (14). An integrating circuit (52) generates the integral of the message signal and applies it to circuitry (54, 56) for generating in-phase and quadrature modulation signals representing the cosine and sine, respectively, of the integrating-circuit output. The vector modulator (14) produces the desired FM signal by adding together quadrature and in-phase versions of a carrier in proportion to the values that the quadrature and in-phase modulating signals represent.

Abstract: According to this invention, a frequency converter comprises a frequency mixer (11) formed in a semiconductor integrated circuit (10), an impedance conversion/signal amplitude limit differential amplifier (12) formed in the semiconductor integrated circuit and connected to the output of the frequency mixer, a first frequency mixing output terminal (14) connected to an output terminal of the frequency mixer and serving as an external terminal of the semiconductor integrated circuit, and a second frequency mixing output terminal (15) connected to an output terminal of the differential amplifier and serving as an external terminal of the semiconductor integrated circuit.

Abstract: An FM modulator includes a base clock generating circuit (7) receiving an incoming video signal for generating an AFC reference frequency signal having a frequency and phase corresponding to a horizontal synchronizing signal of the incoming video signal, a first carrier reset pulse having the same frequency as the horizontal synchronizing signal and a second carrier reset pulse whose frequency is an integer mutliple of that of the horizontal synchronizing signal. The second reset pulse is generated at a timing speed lagged behind the first reset pulse. The FM modulator further includes an adder (3) for adding the first reset pulse to the incoming video signal for lowering the DC level at the leading edge portion of the horizontal synchronizing signal, and an oscillator (9, 9a, 9b, 10, 10a, 10b) whose oscillation frequency is changed dependent on the DC level of the output signal from the adder to produce a carrier FM modulated by the video signal. The oscillator is reset by the second reset pulse.

Abstract: A digital FM modulator (10) which functions to modulate a fixed frequency, e.g. RF, reference signal f.sub.r with an incoming AM analog signal v(t) by way of utilization of digital signal processing circuitry (14, 18, 22, 26, 28, 38, 48). The digital FM modulator 10 includes a digital encoder, e.g. a codec 14, which samples the incoming analog signal v(t) at a prescribed sampling rate f.sub.s, and converts it into a digital signal S.sub.D comprised of successive digital words representative of a prescribed parameter (e.g. amplitude) of the analog signal v(t) at corresponding, successive sampling times t.sub.i. This digital signal S.sub.D is a digital data stream which is subsequently conditioned for input to a direct, digital synthesizer (DDS) (48), which, in response to this input, synthesizes an output signal having I.sub.A and Q.sub.A components disposed in phase quadrature relation to each other. The DDS output signal components I.sub.A and Q.sub.

Abstract: In a direct digital synthesizer providing a frequency modulated output the modulation input is bit shifted and the rate of the direct digital synthesizer phase accumulation is controlled to provide enhanced FM deviation resolution.

Abstract: A frequency modulator is formed in a monolithic integrated circuit as a whole. A direct current signal from a center frequency control circuit and an alternating current signal from a voltage controlled amplifier (VCA) which receives a modulation signal and outputs the alternating current signal are applied to a control input of a voltage controlled oscillator (VCO). A center frequency (Fo) of the VCO is determined by the direct current signal from the center frequency control circuit and a frequency deviation amount (.DELTA.f) of the VCO is determined by the alternating current signal from the VCA, and therefore, a frequency-modulated signal of Fo+.DELTA.f can be outputtd from the VCO. The direct current signal from the center frequency control circuit is also applied to a control input of the VCA, and therefore, the center frequency of the VCO as well as an amplitude of the alternating current signal, that is, the frequency deviation amount can be controlled by only the direct current signal.

Abstract: In a circuit arrangement for the generation of I,Q waveforms, an incoming analog signal controls a voltage-controlled oscillator (1), whose output signal (U1) is frequency-modulated. This signal (U1) is mixed with unmodulated signals by using mixers that are switches (6,7). The signals controlling the switches are either modulated or oscillator-generated rectangular waves. The circuit arrangement can be implemented as an integrated circuit.

Abstract: A facsimile machine includes a MODEM, an attenuator, an NCU and a controller. A signal from the MODEM is adjusted in level by the attenuator under the control of the controller and then output to a transmission line through the NCU. In this case, the adjustment of the level of the signal to be transmitted is carried out in accordance with a predetermined characteristic, such as frequency, of the signal to be transmitted. Also provided is a push phone having a DTMF signal generating circuit and a DTMF signal is also adjusted in level before being output to the transmission line in a manner similar to the signal from the MODEM.