Digital signal

About: Digital signal is a research topic. Over the lifetime, 44213 publications have been published within this topic receiving 345279 citations.

Wideband signal generators, measurement devices, methods of signal generation, and methods of signal analysis

Abstract: A wideband signal generator according to one embodiment of the invention includes a variable frequency source and a direct digital synthesizer. Local oscillators, signal analyzers, modulators, demodulators, and other equipment including one or more such generators are also disclosed.

System and method for the emergency voice and image e-mail transmitter device

Abstract: A voice and image e-mail transmitter device with an external camera attachment that is designed for the emergency and surveillance purposes is disclosed. The device converts voice signals and photo images into digital format, which are transmitted to the nearest voice-image message receiving station from where the digital signal strings are parsed and converted into voice, image, or video message files which are attached to an e-mail and delivered to user pre-defined destination e-mail addresses and a 911 rescue team. The e-mail also includes the caller's voice and personal information, photo images of a security threat, device serial number, and a GPS location map of the caller's location. The digital signal data may be recorded and transmitted within few seconds. The victim's family or police may either check the GPS location map in an e-mail or apply a new GPS based people tracking system of the present invention to search for a missing victim.

Digitally self-calibrating pipeline analog-to-digital converter

Abstract: A self-calibrating pipeline analog-to-digital converter having a plurality of analog-to-digital conversion units and including a recursive calibrating section operable for calibrating errors associated with an immediately preceding first conversion unit. The recursive calibrating section includes circuitry for receiving an analog output signal generated from said first conversion unit in response to an analog input signal provided to the first conversion unit; circuitry for receiving a digital output signal generated from the first conversion unit in response to a digital input signal provided to the first conversion unit; circuitry for generating a conversion signal corresponding to a quantized representation of the analog output signal; and circuitry for generating a calibration signal having a value equal to the conversion signal in response to the digital input signal being a first digital value and having a value equal to the sum of the conversion signal and a calibration value in response to the digital input signal being a second digital value.

Microcontrolled electrocardiographic monitoring circuit with feedback control

Abstract: A microcontrolled electrocardiographic monitoring circuit (10) with feedback control is provided. An input signal path (23) includes an electrode (12a), a low pass filter (13a), and an amplifier (13b) connected in-line. The electrode (12a) senses an input signal and the amplifier (13b) outputs a filtered amplified output signal. A microcontroller circuit (11) includes an input codec, analog-to-digital converter (14), and feedback generation module. The analog-to-digital converter (14) converts the filtered amplified output signal into a data stream (31) of discrete digital values. The feedback module identifies a pairing of drive resistor settings matched to each discrete digital value, which are output as a digital feedback signal. The output signal path (24) includes an electrode (12b) and a buffer (20) connected in-line. A pair of drive resistors (21a, 21b) is connected in parallel to an input terminal of the buffer (20) and to the output terminals of the feedback module. Each drive resistor is adjusted according to the digital feedback signal, and the electrode (12b) provides an output signal.

Linear electric motor controller and system for providing linear speed control

Abstract: The invention relates to a method of, and system for, linear speed control for an electric motor, in which a digital to analog converter means is used for converting an 8-bit digital signal to an analog voltage for setting voltage across a motor, a digital state machine means is used for converting the duty cycle of an input signal for output to the digital to analog converter means, and a closed loop feedback loop means is used for monitoring and setting the voltage across the motor. An over-current sense circuit can be used for monitoring the current across the electric motor. An over/under voltage sense circuit can be used for monitoring voltage of the electric motor. The resulting 8-bit digital control signal is converted to an analog voltage for the electric motor. Such methods and systems find particular use in automotive applications.