Abstract: An electronic component (100) includes a body portion (105) for enclosing first and second electronic devices (415, 430). The component (100) has first and second leads (110, 115) extending therefrom for providing a connection to the first device (415) and third and fourth leads (125, 130) extending from the component (100) for providing a connection to the second device (430). The first device (415) can be a short circuit connection, a fuse, or a resistor, while the second device (430) can be a different device, such as an open circuit connection. When the first and second leads (110, 115) are inserted into a connector (205) of an external circuit (202), the first device (415) is electrically coupled to the circuit (202). When, alternatively, the third and fourth leads (125, 130) are inserted into the connector (205), the second device (430) is electrically coupled to the circuit (202).

Abstract: A connector (100) includes at least one electrical lead for electrically coupling a first device (100) to a second device (210), a base (110) through which the electrical lead (105) extends, and an upper portion (150) through which the electrical lead (105) also extends. A spring mechanism (135) mechanically couples the base (110) and the upper portion (150) and holds the base (110) away from the upper portion (150), and the upper portion (150) includes an upper guide (145) having a hole formed therein. When the connector (100) is in an open position (in which the connector (100) is electrically inactive), the electrical lead (105) does not extend through the hole in the upper guide (150). When the connector (100) is in a closed position (in which the connector (100) is electrically active), the electrical lead (105) extends through the hole in the upper guide (145).

Abstract: An amplifier circuit (400) includes an input port (402) for receiving a signal and a first balun (404) for splitting the signal into first and second signals. First and second amplifiers (406, 408) are coupled to outputs of the first balun (404) for respectively amplifying the outputs of the first balun (404) to generate first and second amplified signals. Second and third baluns (410, 412) are coupled, respectively, to outputs of the first and second amplifiers (406, 408) for splitting, respectively, each of the first and second amplified signals into in-phase and out-of-phase components.

Abstract: A distribution amplifier (210) for a cable television system (100) includes an output gain stage section (215) for receiving an input signal from a cable head end section (105). The output gain stage section (215) includes multiple active amplifier circuits (225, 230) for amplifying the input signal to generate main and auxiliary outputs that are processed by a radio frequency (RF) detector (255) having at least a first detector circuit (300) for processing the main output to generate a first voltage and a second detector circuit (305) for processing the auxiliary output to generate a second voltage. Further included in the distribution amplifier (210) is a status monitor (260) coupled to the RF detector (255) for converting the first and second outputs to first and second digital values and transmitting the first and second digital values. In this manner, an indication of a system or amplifier malfunction can be provided.

Abstract: An amplifier (100) for amplifying signals includes a diplex filter (120) having a highpass filter (110) and a lowpass filter (115), and an amplifier circuit (205) for amplifying higher frequency signals provided by the highpass filter (110) of the diplex filter (120). Because the highpass filter (110) introduces attenuation of the higher frequency signals within a particular frequency range, the amplifier (100) also includes a gain control circuit (155) coupled to the amplifier circuit (205) for adjusting the gain of the particular frequency range. Both the diplex filter (120) and the gain control circuit (155) can reside in a plug-in module that can be inserted into and removed from the amplifier (100).

Abstract: A multi-functional optical isolator that couples radiation from a plurality of input fibers to a plurality of output fibers such that an optical beam emitted from any particular input fiber is transmitted only to its corresponding output fiber. Additionally, an optical beam emitted in the reverse direction from any output fiber is not transmitted back into any of the input or output fibers. The multi-functional optical isolator includes a first focusing lens that collimates the optical radiation emitted from the input fibers and causes them to pass through an optical isolator. The optical isolator has polarizing elements and a magneto-optic polarization rotator. A second focusing lens focuses the optical beams into the output fibers such that the optical radiation from each input fiber is coupled to its corresponding output fiber. Additional off-axis optical elements at other wavelengths may be used for providing bulk-optic coupling of a pump light into a single-mode or multi-mode core of a doped fiber.

Abstract: A method and apparatus for manipulating and de-manipulating Vertical Blanking Interval (VBI) data having any one of a plurality of formats, comprising an encoder, a transmission medium and a decoder. The encoder receives the VBI data having an original data format and manipulates the format of the VBI data into a general VBI format. This signal is transferred to the decoder where the decoder de-manipulate the general VBI format of the VBI data into the original VBI format.

Abstract: A dual-frequency antenna (100) includes a transmit element (110) that is substantially planar and that is formed from a conductive material, such as aluminum, having a loaded slot (140) formed therethrough for transmission of first radio frequencies. The antenna (100) also includes a receive element (115) that is substantially planar and that is also formed from a conductive material having a loaded slot (155) formed therethrough for reception of second radio frequencies. The transmit and receive elements (110, 115) are mounted in a single plane adjacent to a ground plane (105) that is held only a small distance from the transmit and receive elements (110, 115). Preferably, the height of the antenna (100), i.e., the distance between the transmit and receive elements (110, 115), and the ground plane (105) is equal to or less than about 1.4 centimeters for low-profile mounting on truck-drawn trailers.

Abstract: A top-loaded, vertically polarized antenna (10) comprised of two ring radiators (108, 110) formed into loops to provide a dual resonant frequency antenna less than 8 inches on a side for use in the 130 to 150 MHz frequency band. By using separate transmit and receive elements, separate resonant frequencies can be provided without the use of lossy duplexers. The antenna can be concealed inside a housing also containing the radio equipment.

Abstract: An apparatus and method is described for transmitting, receiving and communicating program data signals which are combined with digital data signals. Preferably, the present invention compresses 30 digital audio signals, multiplexes them with title, track, artist, record label, year, etc., program information, and transmits the combined signals via satellite to a receiving station. The receiving station demultiplexes the signals and sends them via a cable distribution system to a subscriber's digital music tuner. This tuner further demultiplexes and decodes the signals so that the digital audio signals may be converted to analog and output for listening, while the corresponding data signals are communicated to the subscriber. In an alternative preferred embodiment, the program data signals are transmitted to a remote control receiver where they are displayed. The system described in the present invention may be used for transmitting video, software or games with program data to subscribers.

Abstract: An amplifier (125) includes a gain stage (210) for amplifying a signal, a variable attenuator (208), such as a Bode circuit, coupled to the gain stage (210) for attenuating the signal, and a signal level control circuit (222, 218, 220) coupled to the variable attenuator (208) and the gain stage (210) The signal level control circuit includes a thermal circuit (218) for measuring a temperature and a removable automatic gain control (AGC) circuit (220) for measuring signal level output by the gain stage (210). An adapter (222) coupled to the thermal circuit (218) and the removable AGC circuit (220) for controlling attenuation of the variable attenuator (208) in response to the temperature when the removable AGC circuit (220) is not electrically coupled to the gain stage (210) and in response to the signal level when the removable AGC circuit (220) is electrically coupled to the gain stage (210).

Abstract: A method for transporting digital data from a sender to a receiver in a system where the digital data is broken into data packets for transmission over radio frequency channels, each data packet including forward error-correcting code, the method comprising the steps of receiving the data packets at the receiver; reconstructing the data packets to the digital data, the forward error-correcting code for fixing corrupted data packets; and halting the data packet reconstructing step if a data packet is uncorrectable.

Abstract: A node (100) for a communications system includes a forward distribution amplifier within a housing (600). Plug-in modules (200,400) can be removably attached to the forward distribution amplifier within the same housing (600) to change the functionality of the node (100). For example, the plug-in module can be a reverse amplifier module (200) for adding reverse signal processing function or an optical module (400) for adding optical capabilities.

Abstract: A communications terminal for receiving digital data services at a location remote from a transmitter comprises a service controller, a bus system, a random access memory and a non-volatile memory. The non-volatile memory preferably comprises FLASH memory. Data is first loaded into random access memory, preferably SRAM and there checked for errors and error-corrected. The data is preferably loaded in blocks into FLASH memory in a predetermined manner to further secure the service data and to permit the use of byte-wide memories accessed as word-wide memories. A service back-up memory is further connected to the bus for storing service data during suspension of play of a service. The service back-up memory preferably comprises a FLASH memory card having its own basic input output service (BIOS) control.

Abstract: A method for defeating illegal receivers sensitive to the edges of synchronization signals in a scrambled video signal is provided. The scrambled video signal includes synchronization signals having levels which prevent a standard receiver from detecting the synchronization signals by using the levels of the synchronization signals. The synchronization signals also have one or more pulses with level transitions above or below a signal detection threshold level of the standard television receiver which prevent the illegal receivers from detecting the synchronization signals by using the edges of the synchronization signals.

Abstract: A graphics blending feature for a terminal such as a home communication terminal (HCT) allows an overlay image to be selectively blended with a background image through the use of a chroma key function and one or more alpha control bits. The chroma key function is used to determine whether the overlay will be completely transparent or not, and the one or more alpha control bits are used to look up a larger alpha value used to blend the overlay and background images. By using a small number of alpha control bits to retrieve a larger alpha value for blending, memory requirements per pixel are reduced. The chroma key function may be implemented by comparing each overlay pixel value to a chroma value and, responsive to a match, making the overlay pixel transparent (i.e., no blending occurs). A dithering function is included in various embodiments to smooth out the resulting image.

Abstract: In an FM television signal angle modulated with luminance and chrominance information, there exists a high degree of correlation between picture elements occurring one line period apart. In an effort to steer the pass band of a tunable bandpass filter to the instantaneous frequency of the incoming television signal, a steering signal is developed which utilizes this high degree of correlation. For NTSC systems, luminance information is delayed by one-line period (63.5 us in the U.S.A.) and combined with suitable delayed chrominance information to form the filter's steering signal. For MAC systems, one-line delayed luminance and two-line delayed chrominance information are alternately applied to the filter as its steering signal. By steering the pass band of the filter to the incoming signal, maximum signal will be captured with minimum noise, enhancing the signal-to-noise ratio of a color television system.

Abstract: A bidirectional communications system is provided for sending signals along a cable in a forward path from a central location to a plurality of remote receiver locations and for sending return signals along the same cable in a reverse path from the remote receiver locations to the central location. The communications system includes a plurality of taps placed along the cable for splitting the signals to be sent to the remote receiver locations, and a radio frequency sensed switch placed at each of the plurality of taps for sensing the return signals so as to turn on the reverse path when the return signals are present and to turn off the reverse path when no return signals are present.