Patent Application
20140256246
1. Field
The present invention relates generally to low-noise block controllers. More specifically, the present invention relates to embodiments for controlling outdoor units of a satellite communication in a plurality of standards via a dual-mode low-noise block controller.
2. Background
Satellite communication may involve transmitting a signal to an orbiting satellite, which relays the signal back to various ground-based receivers. Accordingly, a subscribing unit, such as a household, may receive signals (i.e., audio and video signals) from a satellite via a receiver antenna (e.g., a satellite dish). A digital satellite communication system may include an outdoor unit (ODU), which is placed outside of a structure (e.g., a house, a business, or a vehicle). An ODU typically includes a satellite dish, a feedhorn, a low-noise block (LNB), and possibly a block up converter (BUC). The LNB may configured to receive a signal from the satellite collected by the satellite dish, amplify the signal, down-convert the signal an to intermediate frequency (IF), and convey the down-converted signals to an indoor unit (IDU), which may include an indoor satellite TV receiver, a settop box, a personal computer (PC), a laptop computer, a media gateway, or any other device that can receive a feed from a satellite dish via a cable.
IDUs may be required to support several transport methods as well as ODU interface protocols and hardware deployments, such as Digital Satellite Equipment Control (DiSEqC) for satellite television, and UniCable, which can be used for satellite or terrestrial reception. Commercial LNB controllers support DiSEqC standard and/or UniCable standard. During use of a UniCable standard several client receivers share a common ODU via one RF cable and RF splitter. Further, it may not be possible for a client receiver within a communication system to detect if another client receiver is transmitting. Thus, if two receivers simultaneously transmit, commands may be lost (i.e., due to bus contention and data collisions).
A need exists for controlling ODUs of a communication system in a plurality of modes. More specifically, a need exists for systems, devices, and methods for a dual-mode LNB controller.
The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention can be practiced. The term “exemplary” used throughout this description means “serving as an example, instance, or illustration,” and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary embodiments of the invention. It will be apparent to those skilled in the art that the exemplary embodiments of the invention may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary embodiments presented herein.
Exemplary embodiments, as described herein, are directed to embodiments related to a dual-mode LNB controller. A device may include a controller configured to convey a signal to a low-noise block (LNB) via a transmission line and circuitry configured to sense at least one parameter of the transmission line. The device may further include logic coupled to the circuitry and configured to determine whether the transmission line is available for transmission based on the at least one sensed parameter. As will be appreciated by a person having ordinary skill in the art, the present invention may be applicable to satellite television and communication television networking in, for example, apartment buildings and hotels. Further, the present invention may be implemented within a satellite TV receiver, a settop box, a personal computer (PC), a laptop computer, a media gateway, or any other device that can receive a feed from a satellite dish via a cable.
An LNB controller, which may be part of an IDU, may provide power and control signals to and receive statuses from an ODU. UniCable standard supports a hardware concept where several users share a single ODU via a common transmission line (e.g., an RF cable and RF splitter) having a diode with an anode of the diode connected to a receiver. When UniCable receiver transmits, it asserts a supply voltage of approximately 18 volts. However, because the diodes (i.e., in each receiver or in the RF splitter) are reversed biased, other receivers may not detect the voltage assertion of a transmitting receiver and, thus, UniCable may be susceptible to bus contention
As will be appreciated by a person having ordinary skill in the art, because of a reverse biased protection diode configuration of systems 100 and 120, bus contention and data collision may occur. Accordingly, a receiver, which is asserting a non-transmitting supply voltage (e.g. 13 volts), may not be able to detect transmission by another client receiver, which is asserting a transmitting supply voltage (e.g., 18 volts). Hence, the non-transmitting receiver may not be able to determine whether a BUS, which is shared by multiple receivers, is “busy” prior to sending a signal over the BUS. As a consequence, a BUS collision may exist.
Another problem with UniCable is a minimum current interrupt or a status bit assertion. As will be appreciated, conventional LNB controller circuits may sense a current supply to an ODU and generate an assertion when a current is low to indicate that the cable to an LNB is faulty. However, the receiver, which is at 13V, has an LNB controller with reverse bias protection diode (i.e., as shown in
Further, according to another exemplary embodiment of the present invention, device 200 includes a transistor Q1 coupled between an anode of diode D5 and a resistor R6, which is further coupled to ground voltage GRND. Resistor R6 may also be referred to herein as a “bleeding resistor.” In response to receipt of a control voltage at a gate or base of transistor Q1, the anode of diode D5 may be coupled to ground voltage GRND via resistor R6. Thus, transistor Q1 may form a current bleeding path for use when diode D5 is reversed biased and, thus, false alarms may be reduced since, even though diode D5 is reversed bias because of another IDU transmission to an ODU, a bleeding current through bleeding resistor R6, which is only active in Unicable mode, may be sensed by LNB controller 202 and, thus, a false alarm (e.g., a low-current alarm or a IDU-ODU disconnect alarm) may be avoided. Stated another way, the bleeding current appears as ODU current consumption to LNB controller 202, and therefore, LNB controller 202 does not assert a false alarm.
LNB controller 202 includes a receiver port Rx, a transmit port Tx, and an output voltage port Vout. Receive port Rx is coupled to transmission line 201 via a resistor R1 and a capacitor C1, output voltage port Vout is coupled to DC/DC power circuit 204, which is further coupled to an anode of diode D5, and transmit port Tx is coupled to the anode of D5 via a capacitor C2.
During a contemplated operation of device 200, a voltage on transmission line 201 may be sensed via the voltage divider including resistors R2 and R3. The sensed voltage (i.e., the voltage at node A) may be compared via comparator 206 to a pre-determined reference voltage (i.e., the voltage at node B), which is generated via resistors R4 and R5, to determine whether transmission line 201 if “free” and thus, a DiSEqC transmission is allowed, or if transmission line 201 is “busy”. For example, if the sensed voltage is less than or equal to the threshold voltage (e.g., 13 volts), the transmission line may be “free” and, thus, device 200 may transmit a DiSEqC command via transmission line 201. On the other hand, if the sensed voltage is greater than the threshold voltage, the transmission line may be “busy” and, device 200 may wait before attempting to transmit a DiSEqC command via transmission line 201.
It is noted that, according to one exemplary embodiment, LNB controller 202 may comprise an “off the shelf” LNB controller. According to another exemplary embodiment, as described more fully below, functionality of the voltage sense and current bleeding path circuits may be implemented within an LNB controller.
Further, according to another exemplary embodiment of the present invention, device 300 includes transistor Q1 coupled between the anode of diode D5 and resistor R6, which is further coupled to ground voltage GRND. In response to receipt of a control voltage at a gate of transistor Q1, the anode of diode D5 may be coupled to ground voltage GRND via resistor R6. Thus, transistor Q1 may form a current bleeding path for use when diode D5 is reversed biased and, thus, false alarms may be reduced, as described above.
According to one contemplated operation of device 300, a current though resistor R7 in relation to an output voltage Vout conveyed via controller 202 may be monitored. More specifically, as one example, after a voltage output from controller 202 has been increased, the current through resistor R7 may be monitored via resistors R7-R11 and differential amplifier 306 to determine whether transmission line 301 if “free” and thus, a transmission is allowed, or if transmission line 301 is “busy”. For example, if the current increases after the voltage is increased, the transmission line may be “free” and, thus, device 300 may transmit via transmission line 301. On the other hand, if the current does not increase after the voltage is increased, the transmission line may be “busy” and, device 300 may wait before attempting to transmit on transmission line 301.
It is noted that the current sensing circuitry may also be used to detect a collision that is caused by another IDU, which starts transmitting while device 300 is in the process of transmitting. According to one exemplary embodiment, upon detecting a collision (e.g., by detecting a change in current on transmission line 301), device 300 may stop transmitting data and, after a delay, may attempt to re-transmit the data. According to another exemplary embodiment, upon detecting a collision, device 300 may continue transmitting data and, after a delay, may re-transmit the data to be sure that the data was properly sent.
According to another contemplated operation of device 300, a current flowing though resistor R7 may be measured via resistors R7-R11 and differential amplifier 306 to determine whether transmission line 301 if “free” and thus, a DiSEqC transmission is allowed, or if transmission line 301 is “busy”. For example, if the measured current is equal to or greater than a threshold current, the transmission line may be “free” and, thus, device 300 may transmit a DiSEqC command using transmission line 301. On the other hand, if the measured current is less than the threshold current, the transmission line may be “busy” and, device 300 may wait before attempting to transmit a DiSEqC command on transmission line 301.
As noted above, according to one exemplary embodiment, LNB controller 202 may comprise an “off the shelf” LNB controller. According to another exemplary embodiment, as described more fully below, functionality of the current sense and bleeding path circuits may be implemented within an LNB controller.
As noted above, functionality of the current sense and bleeding path circuits may be implemented within an LNB controller. For example,
The output of differential amplifier 306 may also be routed to a comparator logic 408, which, based upon the current sensing voltage, asserts or de-asserts a “Busy Flag UniCable”. It is noted that a comparator threshold can be configurable. Accordingly, controller 400 provides built-in current sensing and/or an analog current reading to digital demodulator chip for processing according to a method described below with relation to
Additionally, controller 400 includes a voltage sensing circuitry (i.e., resistors R2-R5 and comparator 206). An output of comparator 206 may be routed to AND gate 211 that serves as mask during transmission by applying “Block Flag” from control logic. The output of AND gate 211 is “Busy Flag” signaling a digital chip (SAT demodulator) that it may or may not send a DiSEqC command in UniCable mode. This information may be processed according to a method described below with reference to
Further, controller 400 may be configured to prevent a minimum current error assertion while operating in UniCable mode. More specifically, during operation in UniCable mode, a UniCable configuration bit is set to “0”, as an example, and thereby an AND gate 213 blocks the “Open Cable/Min Current Flag” resulting from the AND gate 213 output “Current Measurement” of current measurement process to propagate to the digital chip by an interrupt or via status bit error. As an example, the “UniCable” configuration bit is set to “1” in UniCable mode based on “Current Sense Out” measurement request when BUS is granted for ODU while performing gated current measurement and asserting “Current Test Gating Signal” or when checking if BUS is free by asserting Voltage to ODU. In both cases “Open Cable/Min Current Flag” fault alarm is prevented by masking it in UniCable configuration.
An IDU, which may include controller 400, may provide an ODU power via controller 400 or controller 400 may serve as serial data transmission interface to the ODU. This depends upon deployment strategy. In a case wherein controller 400 is used as power supply for the ODU in regular DiSEqC deployment, cable fault alarm “Open Cable/Min Current Flag” may be in use and be asserted as a result of current measurement bit output of the AND gate 213. In a case wherein controller 400 is an interface to the ODU in UniCable deployment, cable fault alarm “Open Cable/Min Current Flag” may be masked or ignored using the configuration bit “UniCable” and masking AND 213.
Alternatively, a gated current measurement can be performed as illustrated in
Returning to step 606, if the current is increasing with respect to the voltage, the
BUS is free (depicted by numeral 614), and method 600 may include transmitting data (depicted by numeral 616). Further, method 600 may include waiting for a reply, if needed (depicted by numeral 618). Method 600 may further include reducing the voltage (depicted by numeral 620). For example only, the voltage may be reduced to 13 volts.
Returning to step 602, if the calibration flag has not been set, method 600 may include determining whether other receivers are turned off (depicted by numeral 624). If other receivers are turned off, method 600 may include increasing the voltage (depicted by numeral 626). In addition, method 600 may include measuring the current (depicted by numeral 628) and storing the measured current result (depicted by numeral 630). For example only, the current may be measured at several voltages configured by the LNB controller from the lowest (e.g., 13 volts) to the highest (e.g., 18 volts) including cable loss compensation. Accordingly, a current gradient is mapped and stored. For example, current can be measured a 13.5 volts, 14.2 volts, 18.5 volts, and 20 volts. Moreover, method 600 may include determining whether all voltage values have been calibrated (depicted by numeral 632) and, if so, returning to step 602. If all voltage values have not been calibrated, method 600 returns to step 626.
Returning to step 624, if all other receivers are not turned off, method 600 may include activating another receiver (depicted by numeral 634) and increasing the voltage (depicted by numeral 636). Furthermore, method 600 may include measuring the current (depicted by numeral 638) and storing the measured current result (depicted by numeral 640). The current may be measured at several voltages configured by the LNB controller from the lowest (e.g., 13 volts) to the highest (e.g., 18 volts). Additionally, method 600 may include determining whether all voltage values have been calibrated (depicted by numeral 642). If all voltage values have not been calibrated, method 600 returns to step 636. If all voltage values have been calibrated, the calibration flag has been set and method 600 may return to step 602.
Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the exemplary embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the exemplary embodiments of the invention.
The various illustrative logical blocks, modules, and circuits described in connection with the exemplary embodiments disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
The previous description of the disclosed exemplary embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these exemplary embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the exemplary embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
