Abstract: A bell and method of tuning a bell with its lowest frequency partials at f1=f and f2=3f=2. The simultaneous presence of physical tones at these partial frequencies yields a difference tone, perceived by the listener, at f2f1=3f=2f=f=2. The difference tone is subharmonic, in that its perceived frequency (f=2) is below the frequency of the fundamental (f). Preferably, the bell has one or more additional partials at frequencies fn=(n+1)f=2, with n 2 f3; 4; 5: : : g, strengthening the listener's perception of the difference tone at f=2. The bell thus yields a strike tone at f=2 but has a characteristic dimension (e.g. height or diameter) equal to that of conventional bells with a strike tone at f, providing art eightfold savings in bell mass.

Abstract: A device, particularly a radar sensor, has a voltage-controlled oscillator for generating a high-frequency signal which has an actual frequency, a voltage adjusting device to control the oscillator, and a calibration device operable for adjusting a voltage value which is assigned to a value of a target frequency. The calibration device is operable for finding a difference between a frequency and the target frequency corresponding to the voltage set at the oscillator. The calibration device is also operable for generating a low-frequency signal from the high-frequency signal, determining the oscillation period of the low-frequency signal, calculating an auxiliary frequency from the oscillation period of the low-frequency signal, wherein the auxiliary frequency corresponds to the actual frequency of the high-frequency signal, and for adjusting the voltage value assigned to the target frequency according to the frequency difference between the auxiliary frequency and the target frequency.

Abstract: A digital delta sigma modulator includes an input integration stage, a resonating stage, a quantizer, and a plurality of feedback paths operably coupled to the quantizer, the input integration stage, and the resonating stage. The input integration stage is operably coupled to integrate a digital input signal to produce an integrated digital signal, wherein the input integration stage has a pole at substantially zero Hertz. The resonating stage is operably coupled to resonate the integrated digital signal to produce a resonating digital signal, wherein the resonating stage has poles at a frequency above zero Hertz. The quantizer stage is operably coupled to produce a quantized signal from the resonating digital signal.

Abstract: Apparatus and methods for improving the spectral performance of a polar modulator are described. A composite FM signal component of a composite polar transmit signal may be processed by monitoring the FM signal to detect a transient burst component, and, responsive to detection of a transient burst, generating a spectrally friendly replacement signal component that may be combined with the FM signal to improve spectral performance of the composite signal. In addition, an associated AM component of the composite transmit signal may be filtered to further improve spectral performance.

Abstract: A frequency modulator capable of performing frequency modulation without increasing quantization noise; and a method for adjusting the gain thereof are provided. An input signal is gain-adjusted by a gain adjustment section and outputted to a frequency modulation section. The frequency modulation section is gain-controlled based on a first signal. For setting a digital gain coefficient and an analog gain coefficient of the gain adjustment section, a test signal is inputted. In this state, in a generation section, first control information for setting the digital gain coefficient and second control information for setting the analog gain coefficient are generated based on information regarding a state of the frequency modulation section.

Abstract: A communication device uses a local clock generator to regenerate the carrier frequency of the reference signal from a remote communication. In particular, a closed loop is used to self-calibrate the local pulse till the frequency is fixed to be within a fixed frequency margin. Once the local pulse is obtained, the demodulator will use the local pulse to demodulate the reference signal to generate the data signal.

Abstract: An arrangement for determining a gradient factor for a digitally controlled oscillator has a data alignment device and an identification device. The data alignment device can be supplied a modulation signal, a phase error signal and an oscillator control word. The data alignment device is configured to output a modulation setting word based on the modulation signal, output a time interval magnitude based on the phase error signal and a reference interval, and output an oscillator modulation word based on the oscillator control word. The identification device is configured to adapt and output the gradient factor based on the modulation setting word, the time interval magnitude and the oscillator modulation word.

Abstract: Provided is an AGC circuit which is hard to be influenced by the level of an input signal.

Abstract: A method and apparatus for frequency modulating a PWM involves 1) generating a high frequency carrier signal much greater in frequency than the PWM signal; 2) modulating the high frequency signal to generate a spread spectrum carrier signal; and, 3) retiming a PWM signal with this high frequency SS carrier signal so that the binary transitions of the PWM signal are aligned with the frequency varying carrier signal. In another embodiment, a PWM oscillator is driven by a second, FM oscillator having spread spectrum characteristics. In another embodiment a PWM oscillator is driven and modulated by a counter/frequency divider comprised of modules.

Abstract: Provided is a frequency modulation circuit 1 for outputting a highly precise frequency-modulated signal regardless of variation in a characteristic of a VCO 15. A correction value calculation section 17 calculates a correction value Vt2 based on a voltage value (Vtx?Vt1) resulting from subtracting a control voltage Vt1, which is generated by a control voltage generation section 11, from a control voltage Vtx at which a sensitivity of the VCO 15 is maximized. A variable amplifier 18 amplifies the correction value Vt2. An addition section 13 outputs a control voltage Vt3, which results from adding the amplified correction value Vt2 to the control voltage Vt1, to the VCO 15 via a DAC 14.

Abstract: The present invention relates to an RF integrated circuit comprising a frequency synthesizer and a QAM modulator for modulating a baseband signal of frequency FBB, the frequency synthesizer supplying to the QAM modulator an output signal of frequency F1 adjustable with a frequency step ?F1, for forming a carrier signal of the QAM modulator. According to the present invention, the frequency synthesizer is a Vernier effect frequency synthesizer comprising an auxiliary frequency synthesizer supplying an auxiliary signal of frequency F2 adjustable with a frequency step ?F2 and a main frequency synthesizer having a phase-locked loop bandwidth at least two times higher than the frequency step ?F2 of the auxiliary signal.

Abstract: The phase locked loop (PLL) frequency synthesizer includes a phase detector receiving a reference signal, a controlled oscillator (e.g. a voltage controlled oscillator) connected to the phase detector and generating a synthesized frequency output signal based upon the reference signal, a mixer (e.g. an in-phase and quadrature-phase (IQ) modulator) connected to the controlled oscillator, a divider connected between the mixer and the phase detector, and a signal source driving the mixer. The frequency synthesizer and method have narrow frequency steps (e.g. as low as fractions of a Hertz) while using a relatively high reference frequency to maintain low phase noise. Furthermore, the fine frequency tuning resolution is achieved while also reducing output spurs and using a relatively simple topology.

Abstract: A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase preemphasis coefficients for compensating the frequency conversion gain of the apparatus, and the phase gain coefficient is used for stabilizing a frequency synthesis loop. The phase gain and preemphasis coefficients are determined in a calibration within the time constraints of on-line signal bursts based upon measured phase errors and accelerated predicted phase gain and preemphasis phase errors.

Abstract: A method and apparatus for generating a burst FSK signal having precisely shaped transitions between modulation states. The apparatus uses feedforward compensation of phase gain and phase preemphasis coefficients for compensating the frequency conversion gain of the apparatus, and the phase gain coefficient is used for stabilizing a frequency synthesis loop. The phase gain and preemphasis coefficients are determined in a calibration within the time constraints of on-line signal bursts based upon measured phase errors and accelerated predicted phase gain and preemphasis phase errors.

Abstract: There is provided a VCO having a modulation function capable of easily constituting a correction circuit which can obtain a predetermined modulation degree even when element irregularities are present. A modulation current terminal is connected to an anode side connection point of a first and a second varactor diode. A first resistor is connected between the connection point and an anode side connection point (grounding voltage) of a third and a fourth varactor diode. Voltage deciding the oscillation frequency is input from the voltage input terminal via the second resistor to the cathode side connection point of the first and the third varactor diode and via the third resistor to the cathode side connection point of the second and the fourth varactor diode. A first and a second capacitor are connected from a power source via a first and a second inductor to the cathode side of the first and the second varactor diode.

Abstract: A method for detection and correction of nonlinearities in radio-frequency voltage controlled oscillators provides for division of the output signal of the oscillator, direct analysis of the divided output signal by means of a counting device, conversion of the respective counter value to an equivalent voltage value, and production of a control signal with a corrected frequency response for the oscillator by logic-link the equivalent-voltage value to a predetermined nominal value.

Abstract: A dynamic, self adjusting synchronization system for real time control of the frequency and bandwidth of a modulated signal includes a voltage controlled oscillator for generating a carrier signal to be modulated having a predetermined frequency and bandwidth. There is an adjustment device having a center frequency adjustment circuit for providing a voltage level to the voltage controlled oscillator. A modulation generator generates a modulation signal for modulating the carrier signal to produce a modulated carrier signal and a co-generated measurement signal synchronized with the modulation signal. There is a device for selectively inhibiting the modulation signal.

Abstract: A distortion compensating circuit comprises a frequency control section, a filtering section and an eliminating section. Major frequencies are detected from an input signal including major signals having the major frequencies by a major frequency detector performing spectrum analysis of the input signal. Receiving the major frequencies, the frequency control section calculates distortion frequencies from the major frequencies based on predetermined formulae representing the nonlinear distortion. The predetermined formulae are stored in advance. The frequency control section generates frequency control signals indicating the distortion frequencies. After the input signal is divided into a first signal and a second signal, the filtering section extracts frequency components having the distortion frequencies from the first signal in response to the frequency control signals.

Abstract: A method and apparatus for digital automatic frequency control includes circuitry for frequency controlling a first information portion of a digital input signal, correlating the output with a known characteristic of the first information portion, and outputting a timing signal and channel estimation signal. The digital input signal is also decimated using the timing signal and frequency controlled into a frequency controlled output signal. This signal is used, along with a signal quality estimate derived from the channel estimation signal and first information portion, to determine an estimated frequency correction signal. The estimated frequency correction signal is used to control the frequency correction steps.

Abstract: The effects of long-term drift in a local reference oscillator are compensated by dividing the local reference oscillator frequency by one of three divider patterns (nominal ratio, add a cycle, delete a cycle) so that the symbol clock of the remote terminal is equal to the outroute symbol rate. The number of add a cycle and delete a cycle divider patterns are counted and stored. The average of the number of add a cycle and delete a cycle patterns is used to control the transmit frequency of the remote terminal to correspond to the outroute symbol rate. Thus, the clock recovery process generates a frequency calibration number used to track the frequency of the remote terminal local reference oscillator and to adjust the transmit frequency of the remote terminal accordingly.

Abstract: A digital FM modulating apparatus includes a device for restricting modulation data between a lower limit data value and an upper limit data value which respectively correspond to a minimum allowable frequency and a maximum allowable frequency value of an FM modulated signal. The apparatus also includes a device for suppressing transitional variance in the restricted modulating data and a direct digital synthesizer for receiving the suppressed data and producing synthesized data corresponding to the FM modulated signal.

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 signal processing device for processing an information signal, comprises a frequency modulator arranged to receive the information signal, to frequency-modulate the received information signal and to output a frequency-modulated information signal, a feedback signal generator arranged to receive the frequency-modulated information signal output from the frequency modulator means and to generate a feedback signal therefrom at a phase which is variable to be either in-phase or out-of-phase relative to the received frequency-modulated information signal in accordance with a duty in a high-level period of the received frequency-modulated information signal and at an amplitude which is variable within a range from a zero level to the same level as the received frequency-modulated information signal, and addition circuitry arranged to add the feedback signal output from the feedback signal generator to the information signal received by the frequency modulator.

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.