Abstract: An echo canceller (110) for a full-duplex communication system (100) such as a speakerphone determines a gain factor to be used in sub-band adapter coefficient updates by using both time domain and sub-band signals to determine the state of the system (100). In one embodiment a gain factor controller (120) uses the sampled time domain signal to determine if the system (100) is in the silence state, and if not uses the sub-band signals to determine whether the system (100) is in the talk, double-talk, or listen state. The gain factor controller (120) selectively changes the gain factor and selectively performs coefficient updating based on the state. In another embodiment the gain factor controller (120) determines the state and selectively updates coefficients using state information developed on a band-by-band basis.

Abstract: A method (FIGS. 6-8) for detecting and attenuating N feedback frequencies in a digitized signal uses a tree structure containing a plurality of staged filters. In a step (602), an array of digital filters (FIG. 8) having N branches (40) is constructed. The array is arranged in a tree structure with each branch (40) having several stages (42, 44, and 46). Many of the N filters are used simultaneously in multiple different branches of the tree structure thus reducing the total number of filters required to detect all N feedback frequencies. Within each branch, N-1 of the N filters are notch filters, and each of the N- 1 notch filters attenuates the digitized signal at one of the N feedback frequencies. The remaining one filter in each of the N branches is a bandpass filter that passes the remaining of the N feedback frequency. Therefore, each branch of the tree passes a unique feedback frequency absent of all other N-1 feedback frequencies.

Abstract: A data processing system (10) implements a symmetrical filtering function about the unity gain line using a single filter (33). The data processing system (10) includes a bus (12), an I/O port (12), memory (16), and a processor (18). The I/O port (12) receives filter control parameters (20) and receives and transmits digitized data. The processor receives the filter control parameters (20) and calculates filter coefficients (44, 48, 52). The processor (18) implements the single stage filter (33) based upon the filter coefficients (44, 48, 52) to filter the digitized input data (22) and produce filtered digitized data (24). The single stage filter (33) may include a band pass, high pass, or low pass function. The single stage filtering function (33) produces a filtering function that is symmetrical about the unity gain line. Variable Q operation of the data processing system (10) allows Q of the filtering function to vary with boost/cut level (34).

Abstract: Acoustic feedback is removed from an audio signal (50) by digitizing the audio signal (50) to produce a digitized audio signal (54). The digitized audio signal (54) is then filtered with an adaptive bandpass filter (56) to detect the frequency of the acoustic feedback, where the adaptive bandpass falter (56) is aligned with the feedback based on a phase relationship between the input and the output of the adaptive bandpass filter (56). A notch filter (58) is then configured based on the frequency of the acoustic feedback, and the digitized audio signal (54) is filtered with the notch filter (58) to attenuate the feedback. The feedback-attenuated digitized signal (62) is converted to a feedback-attenuated analog signal (70).

Abstract: A method (100) and data processing system (120) for filtering unfiltered signals (134) to produce filtered signals (136) in accordance with desired filter control parameters (124). Adjusted filter control parameters (130) are generated based upon user provided filter control parameters (124) and operational characteristics (128) of a filter (132) to be implemented. The adjusted filter control parameters (130) are provided to the filter (132) which filters the unfiltered signal (134) to produce the filtered signal (136). Using the adjusted filter control parameters (130), the filter (132) has a filtering function that agrees with the desired filter control parameters (124) to effectively band decouple the filter from bands of surrounding filters. A graphic equalizer (250) implements a multi-band digital filter function that substantially reduces the effects of interband coupling, producing a more accurate match to the original filter response specification.

Abstract: The doff management system of the present invention employs a central computer unit communicating with each yarn processing machine in a textile mill and operating under program control for monitoring and governing the operation of various functions and aspects of the mill operation. The system monitors strand production at each machine and whether the production has reached a predetermined criteria required for doffing; producing schedules of the machines which will be ready for doffing within a forthcoming time period; with the capability of altering the doffing schedules necessary to distribute workload; handling assignment of available doffers to frames which are ready for doffing; tracking earnings of doffers; and monitoring and recording various changes in the production status of the machines and generating current, historical, and prospective reports concerning the textile mill operations.

Abstract: An identification detector and cooperating identification encoder generate an identification signal uniquely correlated to a specific individual one of a group of ring spinning machines which are traversed by at least one traveling unit.

Abstract: Apparatus and method for facilitating efficient management of manufacture by ring spinning machines in a textile mill through the use of a data system wherein sensors are provided on each machine for signalling operating characteristics of the machines, and processors operatively communicating with the sensors and responsive to signals from the sensors determine from such signals the operating conditions of respective ones of the machines. In accordance with this invention, an input device permits entering a request for display of information characteristic of selected individual operating conditions of selected individual spinning machines, with an output device then producing such display.

Abstract: Apparatus and method for facilitating maintenance of a data system gathering information regarding the operating conditions of ring spinning machines in a textile mill wherein at least one traveling unit, supported for travel along a predetermined path for traversing one or more ring spinning machines, carries detectors for monitoring ends of strand material normally being formed by traversed machines, additional sensors are provided on each machine for signalling operating characteristics of the machines, and processors operatively communicating with the sensors and responsive to signals from the sensors determines from such signals the operating conditions of respective ones of the machines. In accordance with this invention, malfunctions of defined portions of the data system are identified and an output display of information characteristic of the nature and machine location of malfunctions is generated.

Abstract: The invention relates to a photo-optical keyboard having an improved keyboard housing and keys to provide an N-key rollover feature. The keyboard is comprised of a keyboard housing and keys, and may have a baseplate. The key has a pair of grooves oriented along the axis for both columns and rows to allow the passage of light regardless if the key is in the up position or the depressed position. The keyboard further contains a reset feature to synchronize keyboard logic if it becomes unsynchronized when partial key depressions are made.

Abstract: A method and apparatus for reducing waste of supply strands passing to a series of yarn processing units, in which a detector moves along the yarn processing units alternately in a first direction and a second direction opposite from the first direction while sensing breakage of any one of a series of strands being delivered from the processing units and also sensing the direction of movement of the detector, and in response to sensing breakage of any strand, and irrespective of the direction of movement of the detector, passage of the corresponding supply strand is interrupted in its course to the corresponding yarn processing unit by a flowing stream of air being directed from a nozzle moving with the detector into engagement with a corresponding, normally inactive, strand interrupting member for actuating the same.

Abstract: Apparatus and method for displaying information regarding the operating conditions of ring spinning machines in a textile mill wherein at least one traveling unit, supported for travel along a predetermined path for traversing one or more ring spinning machines, carries detectors for monitoring ends of strand material normally being formed by traversed machines and a data system responds to the detectors for determining the condition of the traversed machines from the condition of the monitored ends. In accordance with this invention, additional sensors are provided on each machine for signalling operating characteristics of the machines.