A variable wave forming circuit is provided which produces signals of various waveforms (e.g., sine, triangular or trapezoidal waves) and various frequencies. A random access memory (memory means) 121 to store wave formation information on waveform is provided. According to the wave formation information stored in the memory means, the updating or keeping of a digital value in an increment/decrement circuit 123 is controlled and the digital value is digital/analog-converted by a digital/analog (D/A) conversion circuit 124, which is controlled by a digital value control means that includes the increment/decrement circuit 123. By writing appropriate wave formation information into the memory means, it is possible to produce signals of desired waveforms.
The present invention pertains to a method and system for generating a sinusoidal signal as a combination of independently generated sinusoidal signals. A sinusoidal signal consisting of M data points per cycle is generated as a combination of P independently generated sinusoidal signals each consisting of M/P data points per cycle. Each independently generated sinusoidal signal is offset by P-1 data points and interleaved according to a prescribed sequence to represent the combined sinusoidal signal. The system of the present invention utilizes a processing unit having the capability of performing a single instruction on multiple data (SIMD) thereby executing multiple operations per cycle. This architecture enables each data point of the P independently generated sinusoidal signals to be generated simultaneously thereby decreasing the computational expense required to generate the sinusoidal signal.
An audible tone is generated and attenuated over a wide frequency range, such as throughout the human audible range, the tone selectively being of short duration. During a tone period a digital representation of the sine of a requested tone frequency and amplitude is generated. During an attenuation period a digital representation of a moderately disturbed but continuous sine of decreasing amplitude is generated. During a decay period a digital representation of a continuous function which decays to zero from the zero approach point of the sine half wave is generated. During the attenuation period, at zero crossings, the amplitude value is multiplied by a fractional constant; within zero passing zones, the amplitude between subsequent samples is incremented by temporally reduced values to further attenuate the tone and accumulate a bank of accumulated reductions in increments; and while approaching zero crossings, a sine wave of maximum amplitude equal to the amplitude at the beginning of the prior quadrant minus the bank of accumulated reductions in increments during said prior quadrant is generated; and during a decay period, a digital representation of a continuous function which decays to zero amplitude is generated.
A compression treatment system is provided that detects the number of and type of garments connected thereto. The system includes a plurality of ports, valves connected thereto and a number of garments having one or more bladders. The bladders are in fluid communication with a fluid source in a pneumatic circuit, to provide compression therapy once a user confirms the number of and type of garments connected to the system for use by a patient. A single pressure sensor communicates with a plurality of detected bladders located in the one or more garments.
A compression treatment system is provided that includes a first bladder supported about a limb. A second bladder is supported about the limb. The bladders are in fluid communication with a fluid source and the bladders are inflated such that the first bladder is inflated for a first time period and the second bladder is inflated for a second time period. The second time period is initiated within the first time period. A single pressure sensor communicates with the first bladder and the second bladder.
