Bell Telephone Laboratories

Other

Chao Kai Liu

Douglas C Smith

Alexander Feiner

Sigurd G Waaben

Dennis Bryan James

Robert M Smith

Achim Klug

Tim Lei

Zeinab Mohammadi

Various methods and embodiments of the present technology generally relate to neural spike sorting in real-time. More specifically, some embodiments relate to a real-time neural spike sorting process using distributed nodes and edges to form clusters in the vector space to learn the neural spike data distribution adaptively for neural spike classification in real-time. The state of the brain or the onset of a neurological disorder can be determined by analyzing the neural spike firing pattern, and the first stage of the neural data analysis is to sort the recorded neural spikes to their originating neurons. Methods that can sort the recorded neural spikes in real-time with low system latency and can be implemented with resource limited digital electronic hardware, including a Field-Programming Gate Array (FPGA), an Application-Specific Integrated Circuit and an embedded microprocessor, are beneficial in understanding neuronal networks and controlling neurological disorders.

Process and hardware implementation of adaptive real-time neural spike sorting

A gain and frequency compensated barrier circuit is disclosed for use with a telephone transmission line having variable loop lengths. A DC component of the input signal is provided to the input side of the barrier circuit. Loop length losses, as well as barrier gain variations, are adjusted on the output side of the circuit by comparing a barrier DC voltage level with a DC reference level and adjusting the AC gain in accordance therewith. Frequency response, which is also a function of loop length, is corrected by using the DC input voltage to generate an effective loop length dependent capacitor for further controlling the output signal level. An optocoupled circuit is disclosed for use in one embodiment of the disclosure.

Variable loop length compensated barrier circuit

A remote gain controlled optocoupled device is disclosed utilizing a DC reference voltage in the output section to compensate for variations in the optocoupling characteristics of the circuit. The DC voltage level output of the photodetector, which is a function of the light transfer characteristics of the circuit, is compared to a remotely controlled reference DC level. The output AC signal level, which substantially tracks the DC voltage output, is gain adjusted under control of the compared DC voltage levels.

Signal corrected optocoupled device

There is disclosed a protective coupler circuit of the circuit breaker type having a relay contact inserted in the communication line between the key telephone station and the central office in order to protect the central office line from hazardous voltages. A longitudinal unbalance detector is coupled with a metallic high voltage detector to control the relay operation. Circuitry is provided to operate in conjunction with the ring detection circuitry of the key telephone unit to insure proper circuit operation when ringing potential is present on the communication line even though that potential is over the threshold level of the hazardous voltage protector.

Key telephone system optically coupled protective coupler

In order to reduce the signal loss in a telephone line switching and conferencing system there is interposed between each line and the switching matrix a monobus port circuit arranged to convert a transmitted telephone signal into an equivalent current source. An opto-coupled hybrid replaces the port circuit transformer and serves to provide the desired voltage to current conversion. The currents from several monobus circuits are added in a bus resistor before distribution back to the individual monobus circuits as a voltage where the original signal is subtracted from the bus signal. The resultant signal is transmitted to the telephone receiver via the opto-coupled hybrid. When the switching matrix crosspoint resistance is negligible, the component of the bus voltage measured at the current source output which results from current generated from each port circuit is equal and opposite in magnitude to the voltage generated in the port circuit. In any given line these voltages cancel each other, thereby eliminating the feedback signal.

Monobus interface circuit using opto-coupled hybrids

A plurality of idle paths through a multistage switching network which are capable of establishing a connection between a particular line and a particular trunk are identified. Repeated selection of paths identified as idle, but actually out-of-service, is avoided by selecting successively different ones of the identified idle paths in a pseudorandom manner to complete the connection between the line and the trunk. The pseudorandom path selection is accomplished in response to predetermined portions of a pseudorandom pattern of binary bits.

Path-finding scheme for a multistage switching network

In order to reduce the signal loss in a telephone line switching and conferencing system there is interposed between each line and the switching matrix a monobus port circuit arranged to convert a transmitted telephone signal into an equivalent current source. The currents from several monobus circuits are added in a bus resistor before distribution back to the individual monobus circuit where the original signal is subtracted from the bus signal. The resultant signal is transmitted to the telephone receiver. When the switching matrix crosspoint resistance is negligible, the component of the bus voltage measured at the current source output which results from current generated from each line is equal and opposite in magnitude to the voltage generated in the line. In any given line these voltages cancel each other, thereby eliminating the feedback signal. In situations where it is desired to use crosspoints having an unknown resistance, the voltage returned from the monobus does not exactly match the locally generated voltage because of the voltage drop across the crosspoint and thus a feedback signal of unknown magnitude is applied to the telephone line. This unknown deviation of signal gives rise to gain contrast from one connection to the next and modifies the return loss in an unpredictable fashion. This problem has been solved by separating the connections of the monobus into transmit and receive paths and connecting each path to the bus through a separate crosspoint.

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Matawan, NJ, United States of America

Chao Kai Liu