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7570705 |
GMSK modulation using a dual-port memory
A GMSK modulator includes a dual-port memory, an address generator and a signal provider, where the dual-port memory respectively outputs in-phase and quadrature phase waveform data to first and...
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7283012 |
Tri-state pulse density modulator
A tri-state pulse density modulator includes a first switch device coupled to a high voltage, and a second switch device coupled to a low voltage. An adder receives a pulse density modulation (PDM)...
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7065157 |
GMSK modulation techniques
This disclosure is directed to digitally implemented GMSK modulation techniques. The digital GMSK modulation techniques make use of a lookup table (LUT) and mapping logic to digitally generate GMSK...
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6674812 |
High IF frequencies with a lower frequency logic based FSK modulation selecting a harmonic alias and demodulation using sub-sampling techniques
A cost-effective continuous phase logic-based modulator and demodulator are provided to allow communications using binary frequency shift keying (BFSK) as well as M-ary FSK techniques. The...
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6452461 |
High-speed power-efficient coded M-ary FSK modulator
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)...
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6392499 |
Frequency shift modulation circuit
A frequency shift modulation circuit has a direct digital synthesizer DDS and a phase-locked loop PLL. DDS stores output signal frequency data in a plurality of registers. DDS selects the register...
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6324603 |
Data transmission system and game system using the same
To provide a new data transmission system between a game device and related peripheral devices, and a device using same. Serial transmission data is divided into an odd-numbered bit sequence and an...
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6317009 |
Frequency shift key modulating oscillator
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...
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6313772 |
Complex carrier signal generator for determining cyclic wave shape
A method for generating digital carrier signals for application as the carrier to a digital modulator includes providing a first repeating sequence of complex values occurring at a given sample...
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6288618 |
Logic-based architecture for FSK modulation and demodulation
A cost-effective continuous phase logic-based modulator and demodulator are provided to allow communications using binary frequency shift keying (BFSK) as well as M-ary FSK techniques. The...
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6265948 |
Image rejection in logic-based architecture for FSK modulation and demodulation
A cost-effective continuous phase logic-based modulator and demodulator are provided to allow communications using binary frequency shift keying (BFSK) as well as M-ary FSK techniques. The...
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6163229 |
Frequency generator for generating two independent FSK signals
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...
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6002304 |
Data modulation system using digital signal processing
A modulation system is provided with a data analyzer detecting input of a modulated data and a modulation clock signal and latching and detecting an edge of the modulated data, in response to the...
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5942955 |
Quasi-GMSK modulator
In order to provide a digital GMSK modulator operating sufficiently stably without aliasing distortion even with a sampling rate of twice of that of input signal, a quasi-GMSK modulator of the...
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5926072 |
FM modulator using a monostable multivibrator
A frequency modulation circuit includes an emitter-follower connection transistor (2), having a base supplied with a modulation signal, for generating an emitter voltage which is in proportion to a...
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5889443 |
Frequency synthesizing circuit using a phase-locked loop
A frequency synthesizing circuit has an input on which a bit flow is received, and an output on which a data-modulated output signal is supplied. The circuit moreover comprises a crystal oscillator...
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5838208 |
Modulation of transmission data signal in sychronous with transmission clock signal
In a modulating system, a converting unit generates first and second quadrature signals based on a transmission data signal in synchronous with a transmission clock signal. First and second filters...
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5835539 |
FSK modulator
The FSK modulator for modulating binary data of the present invention has an object to provide an FSK modulator which can operate at a stable frequency also when a discontinuous data row is...
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5789991 |
FSK modulating and demodulating apparatus wherein each binary data is represented by same number of cycles of modulated signal
A signal FSK-modulated with a binary data signal has first signal portions representing first logical level data contained in the binary data signal and second signal portions representing second...
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5627499 |
Digital modulator and upconverter having single-bit delta-sigma data converters
A method and apparatus for digitally phase modulating and frequency upconverting communication signals to an intermediate frequency, producing the IF output with only digital hardware and without...
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5485129 |
Method and apparatus for digital modulation using pulse deletion
An apparatus (500) for generating first and second output signals having predetermined frequency shifts relative to a frequency provided by a reference signal is included in a system comprising a...
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5444415 |
Modulation and demodulation of plural channels using analog and digital components
In the modulation and demodulation of a plurality of frequency separated channels on a radio frequency carrier by digitally coded speech or data, the speech or data is modulated on a digitally...
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5399998 |
Digital FM modulator
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...
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5382924 |
Continuous phase frequency shift keying modulator
A modulator is adapted for use in a transmitter of an information transmission signal in which the information is in the form of a frequency shift keyed code. The signal is centered on a fictional...
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5365548 |
Digital FSK transmitter
A digital FSK transmitter utilizing a clock feedback signal driving an accumulator to operate a pair of registers having a pair of preset numbers stored therein to selectively add said numbers...
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5361046 |
Modulator having fractional sample/symbol time
A modulator capable of providing a fractional sample or symbol 995486 time employs a decimation counter (23) responsive to a clock having a frequency equal to M/N×(data symbol clock), where M is...
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5289141 |
Method and apparatus for digital modulation using concurrent pulse addition and subtraction
A method and apparatus for generating an output signal (616) having a pre-determined frequency shift relative to the frequency of a reference signal from a reference frequency generator (202)...
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5216391 |
MSK modulator having a digital quadrature reference waveform generator
An MSK modulator providing a high precision digital phase adjustment with a simple circuit structure. A sample data of a sine wave or cosine wave is read from a memory at an address calculated from...
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5187721 |
Frequency shift keying modulator
The present invention provides a modulator/generator circuit which includes the following features: a 1200 baud 4-phase differential phase shift keying (DPSK) modulator, a 300 baud frequency shift...
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5073903 |
Information transmission arrangement using frequency modulation
A control circuit (10) controls a voltage controlled oscillator (15) to cause the signal at the output of the oscillator to have slopes of frequency variation in accordance with biphase encoded...
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5020075 |
Direct sequence spread spectrum modulation apparatus
In a direct sequence spread spectrum modulation apparatus, the data of predetermined bit inserted in a phase shift time data period provided between the respective PN codes, or a predetermined bit...
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4924482 |
Data-transmitting apparatus
The analog data representing a value measured of a product by means of a measuring device such as a vernier calipers is converted into digital data by an analog-to-digital converter. A CPU...
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4878035 |
Hybrid frequency shift keying modulator and method
A hybrid frequency shift keying modulator and method produces binary FSK by simultaneously applying a digital modulating signal to the DDS section of a frequency synthesizer along with a...
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4757519 |
Digital premodulation filter
A programmable premodulation filter having a finite impulse response to digitally filter a digital data signal to provide a modulation signal for modulating an RF carrier signal is described. A...
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4748640 |
Digital circuit with band limiting characteristics for modem
The input digital signal is applied to a transition detector which causes an up/down counter to increment or decrement each time a transition is detected. The output of the counter is utilized to...
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4724534 |
Method and apparatus for transmitting binary data signals by frequency shift keying
A modulator for modulating binary data signals by frequency shift keying (FSK), in which a binary data level 1 is represented by a first frequency (f 1 ) and the binary data level 0 is represented...
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4686688 |
Arrangement for generating an angle-modulated carrier signal of a constant amplitude in response to data signals
An arrangement for generating an angle-modulated carrier signal of a constant amplitude and continuous phase φ(t) comprises a control circuit which in response to a given number of consecutive...
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4686490 |
Digital data modulator and digital-to-analog converter
A digital modulator for selectably generating differential phase shift keyed (PSK) data signals and frequency shift keyed (FSK) data signals is disclosed. A clock generator (10) provides carrier...
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4656646 |
Serial minimum shift-keyed modem
An apparatus and method is disclosed of an SMSK/2 device that provides an additional phase state, and having at least three phase changes possible per bit period, as compared with standard SMSK/2...
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4648099 |
Digital minimum shift keyed modulator
A digital minimum shift keyed modulator (MSK) has been described incorporating a code generator for generating a plurality of bits in series representative of a spreading function, an Exclusive OR...
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4625318 |
Frequency modulated message transmission
A data signal is encoded as frequency modulation by selecting carrier sources of different phases in response to data signals and filtering the resultant wave to produce an output deviating from...
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4584540 |
Digital direct modulator with type of modulation selection
The present invention uses digital values of MSK-like waveshapes which can be stored in a storage media such as a ROM and then output in a prescribed fashion such as in phase quadrature through the...
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4569060 |
FSK Coding method and apparatus involving multiples and submultiples of a given frequency
A method for coding a data signal for transmission and reception which includes the steps of generating a prefix signal which is a train of pulses at a multiple or submultiple of a selected...
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4543541 |
FSK modulation using switched outputs of two oscillators
Two oscillators are utilized to convert digital data into an FSK modulated signal. One oscillator is at the mark frequency and the other is at the space frequency. FSK modulation is accomplished by...
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4539533 |
Digital MSK modulator
A digital apparatus for performing minimum-shift-keying (MSK) modulation includes an oscillatory circuit which provides two frequencies related in a predetermined manner, and also includes a...
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4523158 |
Clock regenerator using two on-off oscillators
A clock pulse regenerator uses a pair of oscillators each comprising a NOR gate and a transmission line feedback element. The oscillators are provided with complementary data pulses and provide an...
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4500856 |
Simplified minimum shift keying modulator
An MSK modulator having a simple construction with only a single necessary adjustment. The digital bit stream to be modulated is fed directly to the control input of a 0,π phase shifter in a...
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4426710 |
Processes for generating duo-binary FSK, tamed FSK and TFM modulations and modulators applying those processes
To obtain a duo-binary FSK modulation, the modulating binary signal train has a three state partial response and is fed through a precoding, a transition-type coding, a simplified MSK modulation at...
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4425665 |
FSK Voiceband modem using digital filters
An asynchronous FSK modulator-demodulator (modem) having a capability of operating at data rates of 300, 600 and 1200 bits per second in a voiceband telephone channel is compatible with the...
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4411005 |
Data circuit for frequency modulating an oscillator
Data signals which vary between first and second levels are applied to an operational amplifier by a timing signal produced in response to data signal transitions. The operational amplifier is...
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