Abstract: The present invention relates to a protocol test device including a network processor where the network processor has the following features: protocol levels of a protocol stack can be programmed in it for at least one protocol per software; it is capable of simultaneously processing input signals of different transmission formats, in particular of different clock rates; a plurality of channel ports for network subscribers in parallel architecture; and one standardized interface for a control unit; with the network processor being designed for in-stream operation, i.e. signals arriving at the ports for network subscribers can be redirected to at least one other port for network subscribers, if necessary after a pre-processing step. A host processor which has been programmed for performing protocol emulations and/or simulations is coupled to the network processor, with the signals of the network subscribers forwarded to the channel ports terminating in the protocol test device.

Abstract: A system and method for subscriber tracking and creating subscriber records in a GPRS or UMTS network is disclosed. A local mapping record is created on a probe monitoring a Gi interface upon the detection of Access Start messages. Additional information is sent from a probe monitoring a Gn/Gp interface, and this information is added to the local mapping record. The processing of captured messages and the creation of local mapping record is prioritized to ensure that records for different subscribers who used the same IP address are not improperly combined. Finally, Gi traffic is tagged with unique subscriber information, such as the International Mobile Subscriber Identity (IMSI), not previously present on the Gi network.

Abstract: A system and method for subscriber tracking and creating subscriber records in a GPRS network is disclosed. First subscriber records are created using information from first data packets captured from a first GPRS network interface. The first subscriber record is compared with information in second data packets captured from a second GPRS network interface. If the second data packets are associated with the first subscriber record, then information from the second data packets is added to the first subscriber record. If the second data packets are not associated with the first subscriber record, then a second subscriber record is created using information in the second data packets.

Abstract: A method of software clamping a video signal for waveform display on a general purpose oscilloscope where the video signal is a.c. coupled to an input of the oscilloscope includes acquiring samples of the video signal in response to a trigger signal derived from the video signal, which samples are then stored. Then samples relative to the trigger signal that are at a nominally known voltage are retrieved, averaged and compared to a reference value. The reference value may be a value determined from a first acquisition of the video signal or a value corresponding to the nominally known voltage. The difference between the averaged samples and the reference value is then used to adjust the sample values when retrieved for display by the oscilloscope.

Abstract: A system is disclosed for equalizing the distribution of pixel intensities in an image displayed by an oscilloscope. In a primarily software implementation, the maximum pixel intensity (I) present in the rasterized input image, the maximum available display intensity (P) and the desired image resolution (R) are the input variables which permit the calculation of thresholds or bins to which each pixel is assigned. By iteratively performing the analysis of existing pixel intensities and bin thresholds, the number of pixels in each bin may be optimized to form an equalized histogram. Another implementation of the histogram equalization system utilizes software to optimize a hardware-based histogram collector.

Abstract: A time history display of orthogonal code power levels by spreading factor is generated by displaying each data record of code domain power as a line, with each point in the line representing a different code index and the color or brightness of each data point representing the associated base code power level. With the data records displayed as contiguous lines, as each new data record is acquired it is added as a new line of the display while the line representing the oldest data record is deleted from the display. For communications standards where the code spreading factor varies, both bit-reversed and Walsh code graphs are displayed to show the grouping of the sub-codes that make up a base code. In this way the time history display indicates timing and trend information to a user.

Abstract: A differential measurement probe has spring loaded probe assemblies and a pressure sensors disposed in a housing. The pressure sensors forms an electrical switch having an electrical AND function for passing an activation signal to a EOS/ESD protection control module in response to axial movement of the housing relative to the probe assemblies. First compressive elements produces first pre-loaded compressive forces and increasing compressive forces on the probe assemblies and second compressive elements produces second pre-loaded compressive forces and increasing compressive forces on the probe assemblies subsequent to the first increasing compressive forces on the probe assemblies.

Abstract: An insulated Bayonet Neill Concelman (BNC) connector includes a replaceable non-metallic insulating shell. The non-metallic shell is attached to a metallic portion of the BNC connector such that, when mounted on an oscilloscope, or other electronic instrument, the non-metallic shell may be disconnected from the metallic portion of the BNC connector without having to gain access to the interior of the instrument housing. Thus, in the event of damage to the non-metallic shell, the damaged non-metallic shell may be quickly and easily replaced by a user, instead of having to return the instrument to the manufacturer for repair.

Abstract: An electrical isolation device wherein a signal to be electrically isolated is mixed with a carrier signal by a multiplier to produce a modulated carrier signal which is passed through an isolation barrier and demodulated and filtered to extract thereby the initial input signal.

Abstract: An activity display for multiple data channels over a period of time for a communication link provides a quasi-three-dimensional presentation having time periods and data channels as orthogonal axes and shading within each time period/data channel rectangle representing ones density for the channel during that time period. One or more frames of the communication link corresponding to one time period are captured, and then each frame is processed in sequence one data channel at a time to build up a line of the display for the time period. Over multiple time periods the display is built up line by line, with the oldest line being dropped as a new line is added when the maximum number of lines for the display is achieved. In this way an operator has a high level all-in-one glance at the operation of the communication link.

Abstract: The subject apparatus and method measures the Total Average Power Loss and isolates the different power loss components of Total Average Loss such as Ton Loss and Toff loss at switching devices such as, MOSFETs, BJTs and IGBTs that may be used in a switching power supply. It provides separation of the components of Total Average Loss as Turn Ton Loss, Turn Toff Loss and allows derivation of conduction loss. It also has the capability to measure Total Average Loss and Switching Loss, while amplitude, duty cycle and frequency of the switching signal is varying in a switching power supply.

Abstract: An electronic instrument has a rotary switch with an extending shaft, a light source proximate to the shaft, and a knob attached to the shaft. The knob has a body with a rear face, an opposed front face, and side surfaces extending between the faces. The rear face defines a bore sized to receive a free end of the shaft. The body has a light-transmissive portion extending from a first surface portion of the rear face surrounding the bore, such that light from the light source enters the light transmissive portion regardless of the rotary position of the knob. The light-transmissive portion of the body extends to a window in the side surface or the front face.

Abstract: A picture quality diagnostics apparatus and method generates a human vision model response based on a human vision model for a test input video signal. Also objective measure maps for different impairment types are generated from the test input video signal. The objective measure maps are applied as masks to the human vision model response to produce objectively filtered subjective maps. The objectively filtered subjective maps are analyzed to give the respective proportions of the different objective impairment types contributing to perceptual impairment or difference for the test input video signal.

Abstract: A method for determine blurring in a test video sequence due to video processing includes detecting blocks within each frame of the test video sequence that have valid image edges. An edge point within each valid image edge block is selected and a series of points defining an edge profile in the block along a line normal to the valid image edge at each edge point is defined from an enhanced edge map in which video processing blockiness artifacts have been removed. From the edge profile a blurring value is estimated for each frame or group of frames within the test video sequence. Additionally a reference blurring value may be derived from a reference video sequence corresponding to the test video sequence, which reference blurring value may be generated at a source of the reference video sequence and transmitted with the test video sequence to a receiver or may be generated at the receiver.

Abstract: Apparatus for rapidly acquiring a large number of samples of a signal under test, stores the samples in a waveform memory without converting the samples to binary form. The signal under test is applied to an arrangement of comparators and exclusive-OR gates to provide a signal indicative of amplitude. The waveform memory is arranged in rows and columns. In one embodiment, the amplitude-indicative signal serves as a row address signal for the waveform memory, and a scanning control signal serves as a column address signal for the waveform memory. In another embodiment, an X-Y display is produced in which the column address signal is responsive to the amplitude of a second signal under test.

Abstract: A system and method for measuring user-perceived delay in an IP network, comprising detecting request and corresponding response messages at a monitoring point in the network, calculating an uplink delay based upon the time elapsed between the request and corresponding response messages, detecting response and corresponding transport acknowledgement messages at the monitoring point, wherein the response message is sent in response to the request message, calculating a downlink network delay based upon the time elapsed between the response and corresponding transport acknowledgement messages; and calculating a user-perceived delay by adding uplink delay and downlink network delay, wherein the user-perceived delay represents a time required for an IP message to travel from a user device to a network destination plus the time required for the service (server) to respond and return the response to the user device.

Abstract: An artistic color gamut display is generated by obtaining maximum and minimum values for an RGB signal. The maximum and minimum values are used as X and Y values for an XY plot. A triangular graticule, or Spearhead display, is generated for the XY plot having a first side representing Lightness, a second side representing saturation and a third side representing Value. The area within the Spearhead display represents valid color gamut. The Spearhead display may be combined with more traditional displays, such as Vector or Arrowhead displays, to provide a completely three-dimensional analysis of the RGB signal in terms of the artistic parameters of Hue, Saturation and Value or Lightness.

Abstract: A phase locked loop type frequency synthesizer utilizing a reference signal source includes a voltage controlled oscillator (VCO), a phase comparator, a programmable pre-scaler and a modulator. The programmable pre-scaler divides the output of the VCO according to a sequence of divide ratios to produce a divided signal having a frequency approximating the reference signal frequency. The phase comparator compares the phases of the divided signal and the reference signal and, in response to a difference, adapts the VCO to reduce the detected difference. The modulator provides a next value in the sequence of divide ratios by accumulating an error between a present value and an average value in the sequence of divide ratios, accumulating the accumulated error values, and determining the next value in the sequence of divide ratios such that the multiply-accumulated error values are maintained within finite bounds.

Abstract: A method and apparatus for processing anomalous trigger event conditions to provide anomalous trigger event rate measurements. The apparatus operates to identify one or more trigger events in at least one input signal IN, determine the number of events during a period of time (e.g. events per second) and provide a visual representation of this determination to a user via a display device. The visual representation may comprise an alphanumeric display, a waveform, a graphic image proximate a waveform and the like.

Abstract: A method and apparatus for an improved timer circuit and improved pulse width detection includes initiating a ramp timer and setting a timer latch output level substantially simultaneously in response to the occurrence of an input signal. The occurrence of the input signal also causes a counter to be enabled to count clock cycles. The ramp timer signal of the ramp timer is frozen (i.e., paused) by a timer control circuit, upon the occurrence of a first clock cycle following the enabling of the counter. The counter then counts a predetermined number of clock cycles after the ramp timer signal is frozen and, upon the occurrence of a last one of a predetermined number of clock cycles, generates a terminal count signal. Upon receiving the terminal count signal, the timer control circuit unfreezes ramp timer signal. The ramp timer runs until completion at which time the ramp timer generates an end of ramp control signal. The control signal is communicated to timer latch to reset timer latch output level.