摘要:
A dual tone multi-frequency (DTMF) receiver for use in detecting digitally transmitted signals in the telephone industry. The receiver derives linear predictive coefficients for the digital signals in the data frame. This information is used to compute frequency response magnitudes at the DTMF frequencies. A plurality of magnitude comparisons are then performed to verify the presence of true DTMF signals and concurrently the frequency of these signals is obtained.
摘要:
In recent years, the telecommunications industry has witnessed the proliferation of a variety of digital vocoders in order to meet bandwidth demands of different wireline and wireless communication systems. The rapid growth in the diversity of networks and the number of users of such networks is increasing the number of instances where two vocoders are placed in tandem to serve a single connection. Such arrangements of low bit-rate codecs can degrade the quality of the transmitted speech. To overcome this problem the invention provides a novel method and an apparatus for transmitting digitized voice signals in the wireless communications environment. The apparatus is capable of converting a compressed speech signal from one format to another format via an intermediate common format, thus avoiding the necessity to successively de-compress voice data to a PCM type digitization and then recompress the voice data.
摘要:
A speech bandwidth extension method and apparatus analyzes narrowband speech sampled at 8 kHz using LPC analysis to determine its spectral shape and inverse filtering to extract its excitation signal. The excitation signal is interpolated to a sampling rate of 16 kHz and analyzed for pitch control and power level. A white noise generated wideband signal is then filtered to provide a synthesized wideband excitation signal. The narrowband shape is determined and compared to templates in respective vector quantizer codebooks, to select respective highband shape and gain. The synthesized wideband excitation signal is then filtered to provide a highband signal which is, in turn, added to the narrowband signal, interpolated to the 16 kHz sample rate, to produce an artificial wideband signal. The apparatus may be implemented on a digital signal processor chip.
摘要:
A multi-process scheduler applies a joint optimization criterion to jointly schedule multiple processes executed on a shared processor. The scheduler determines, for each one of a plurality of processes having a predetermined processing time, at least one of an expected arrival time for input data and required delivery time for output data. The scheduler jointly determines process activation times for the processes based on said arrival/delivery, and the processing times, to meet a predetermined joint optimization criterion for the processes. The processes are scheduled on the shared processor according to the jointly determined activation times to minimize queuing delay.
摘要:
The present disclosure provides systems and methods for dynamically signaling encoder capabilities of vocoders of corresponding communication nodes. In one embodiment, during a call between a first communication node and a second communication node, a control node (e.g., base station controller or mobile switching center) for the first communication node sends capability information for a voice encoder of a vocoder of the first communication node to a control node for the second communication node. As a result, the second communication node is enabled to select and request a preferred encoder mode for the voice encoder of the vocoder of the first communication node based on the capabilities of the voice encoder of the vocoder of the first communication node.
摘要:
A multi-process scheduler applies a joint optimization criterion to jointly schedule multiple processes executed on a shared processor. The scheduler determines, for each one of a plurality of processes having a predetermined processing time, at least one of an expected arrival time for input data and required delivery time for output data. The scheduler jointly determines process activation times for the processes based on said arrival/delivery, and the processing times, to meet a predetermined joint optimization criterion for the processes. The processes are scheduled on the shared processor according to the jointly determined activation times to minimize queuing delay.
摘要:
A network entity, which comprises an input configured to receive from an upstream network entity a stream of first media data elements; an output configured to release towards a downstream network entity a stream of second media data elements; a processing engine configured to effect processing tasks on the first media data elements, thereby to generate the second media data elements, the processing tasks being effected in a set of processing intervals; and a control entity. The control entity is configured for receiving a request for a first phase adjustment from the downstream network entity; modifying the set of processing intervals in which are effected the processing tasks in an attempt to accommodate the first phase adjustment; determining a second phase adjustment based on arrival characteristics of the first media data elements and the modified set of processing intervals; and releasing towards the upstream network entity a request for the second phase adjustment.
摘要:
In a TDMA mobile-to-mobile connection, the end-to-end audio signal quality as well as system performance can be improved by providing digital signal processors the capability to automatically switch configuration such that each digital signal processor in a mobile-to-mobile communication connection can automatically identify a TDMA mobile-to-mobile connection and bypass the speech encoding and decoding processes within the digital signal processors. The two digital signal processors are virtually connected at the channel codecs.
摘要:
In methods and apparatus for suppressing echo of a far end signal encoded using LPC-based compression in a near end signal encoded using LPC-based compression, parameters of each frame of the near end encoded signal are processed without synthesizing a speech signal from the near end encoded signal to determine whether sufficient echo to merit echo suppression is present in the frame. Upon determining that insufficient echo to merit echo suppression is present in the frame, the parameters of the frame are passed unmodified. Upon determining that sufficient echo to merit echo suppression is present in said frame, the parameters of the frame are modified without synthesizing a speech signal to suppress echo in the frame. The methods and apparatus are particularly suitable in codec bypass applications.
摘要:
In a TDMA mobile-to-mobile connection, the end-to-end audio signal quality as well as system performance can be improved by providing digital signal processors the capability to automatically switch configuration such that each digital signal processor in a mobile-to-mobile communication connection can automatically identify a TDMA mobile-to-mobile connection and bypass the speech encoding and decoding processes within the digital signal processors. The two digital signal processors are virtually connected at the channel codecs.