Abstract: A communication system (100) processes forward signals generated by headend equipment (105) and reverse signals generated by subscriber equipment (135). A communication medium (110, 120), such as fiber optic cable or coaxial cable, connects the headend equipment (105) and the subscriber equipment (135), and amplifiers (400) are positioned at various locations along the medium (110, 120) to amplify the forward and reverse signals. The amplifiers (400) include a dual forward/reverse test circuit (FIG. 6) having a forward test point (406) coupled to the forward signal, a reverse test point (408) coupled to the reverse signal, and a single directional coupler (404) connected to the forward test point (406), for providing the forward signal thereto, and to the reverse test point (408), for providing the reverse signal thereto.

Abstract: A communication system (100) processes forward signals generated by headend equipment (105) and reverse signals generated by subscriber equipment (135). A communication medium (110, 120), such as fiber optic cable or coaxial cable, couples the headend equipment (105) and the subscriber equipment (135), and amplifiers (400) are positioned at various locations along the medium (110, 120) to amplify the forward and reverse signals. The amplifiers (400) include a dual forward/reverse test circuit (FIG. 5) having a forward test point (406) coupled to the forward signal, a reverse test point (408) coupled to the reverse signal, and a single directional coupler (404) connected to the forward test point (406), for providing the forward signal thereto, and to the reverse test point (408), for providing the reverse signal thereto.

Abstract: An analyzer for electrophoretic samples includes a sensor of extremities, more particularly valleys, in the output from the detector. The analysis of electrophoretic samples includes integration of the area under each of the fractions of the multicomponent output. In order to integrate each of the components, it is necessary to detect valleys in the output. The detector output is first applied to a non-linear processor such as a logarithmic amplifier and a differentiator. The logarithmic amplifier changes the shape of the output to make the detection less dependent upon relative component amplitude. A threshold comparator produces a pulse when the slope of the analyzer output, as represented by the output of the differentiator, exceeds a threshold. The threshold is changed after the detection of the first valley. Noise suppression circuitry prevents the detector from responding to closely occurring extremities in the analyzer output.

Abstract: An analyzer for electrophoretic samples has a sample stage movable linearly with respect to a source and a detector of analysis energy. During a first scan of the sample, a voltage is produced representing either the minimum detected fluorescence or the minimum detected optical density. During a second scan, the voltage is combined with the output of the detector to automatically correct the output to a reference.

Abstract: An integrator for continually computing the area under a curve drawn by a chart recorder, and displaying the area information by superimposing small spikes on the curve. The integrator uses a voltage-to-frequency converter that derives its input from the signal source to generate the spikes. A frequency divider circuit can be used so that every nth spike is larger or negative, making readout easier. The spikes and the analog signal are electronically added and the resulting signal is connected to a standard laboratory pen chart recorder. The area under any selected portion of the chart curve is found by counting the spikes on the curve.

Abstract: An improved method for graphically displaying optical density patterns generated by a densitometer which scans a sample to generate analog signals indicative of the optical density of the sample. The maximum amplitude and cumulative amplitude of the analog signals are computed and stored simultaneously as normalizing signals. The sample is again scanned to recreate the analog signals which are directed in two paths toward two graphic display units. The recreated analog signals directed toward the first display unit are modified by the normalizing amplitude signal to create a visual display curve of the normalized density. The recreated analog signals directed toward the second display unit are modified by the normalizing cumulative amplitude signal to create a visual display of the normalized area under the density curve.The apparatus includes a scanning system having circuitry to provide analog signals indicative of the optical density of the sample and a pair of conventional graphic display devices.

Abstract: A method of detecting psychological stress by evaluating manifestations of physiological change in the human voice wherein the utterances of a subject under examination are transduced to electrical signals and processed to emphasize selected characteristics which have been found to change with psycho-physiological state changes. The processed signals are then displayed, as on a strip chart recorder, for observation, comparison and analysis. An especially useful characteristic is an infrasonic modulation in the voice. Apparatus for performing detection of this type includes a transducer, a magnetic recorder, a series diode, a plurality of integrating capacitors, an amplifier and a chart recorder. A second apparatus includes filter means, an FM discriminator and a detector, a waveform integrator, an amplifier and a recorder for producing a visible record.

Abstract: Apparatus for producing a graph of a function represented by a varying analogue input signal supplied to the apparatus, comprising display means adapted to display in a graphing operation the graph of the function, calculating means adapted to receive the analogue input signal and to calculate the value of a parameter of the function, and control means operable to interrupt the operation of the display means at preselected points in the graphing operation and to cause the display means to display the value calculated by the calculating means and thereafter to resume the graphing operation.