WO1998014004A1

WO1998014004A1 - A system and method for radio frequency conversion and distribution

Info

Publication number: WO1998014004A1
Application number: PCT/US1997/017218
Authority: WO
Inventors: David Medin; Paul J. Weihs
Original assignee: Innovision Labs, Inc.
Priority date: 1996-09-25
Filing date: 1997-09-25
Publication date: 1998-04-02
Also published as: AU4501797A

Abstract

A radio frequency (RF) converter/distributor device (100) for converting a baseband signal (30) into a RF signal and for distributing the RF signal to an input device, such as a television (110), that receives a power signal through a power cord (108). The RF converter/distributor device (100) includes an input (102) for receiving the baseband signal (30), a digital RF modulator (104) coupled to the baseband signal (30) for converting the baseband signal (30) into RF signal, and a RF distributor (106) coupled to the power cord (108) for inducing the RF signal onto the power signal for reception by the input device. In addition, the RF modulator (104) is programmable such that the RF signal is selectable for compatibility with a plurality of RF standards.

Description

A SYSTEM AND METHOD FOR RADIO FREQUENCY CONVERSION AND DISTRIBUTION

FIELD OF THE INVENTION

The present invention relates to RF signal conversion and distribution, and more specifically to a system and method for converting computer video and/or audio signals into a television compatible RF modulated composite signal and to a system and method for distributing the RF signal.

BACKGROUND OF THE INVENTION

Typically electronic devices output unmodulated baseband signals that have a (DC) component. Baseband signals may either be analog or digital, and may include both a video and an audio component. Examples of electronic devices that output analog baseband signals include hand-held portable stereos that output audio information only, and camcorders that may output both video and audio information. The analog video baseband signal output from a camcorder is typically sent to a television or other type of monitor for display. Figures la and lb are a block diagrams depicting a conventional analog baseband signal 30a. The analog signal 30a includes a series of video lines 32, shown here as 32a, 32b, and 32c, each of which corresponds to scan lines on a television or display screen. Each video line 32 includes a series of values 34 that control the chrominance and luminance for N pixels in a scan line, where the number N of values 34 in a video line 32 depends on the resolution of the image.

Each of the values in the video lines 32 are represented by voltages, where white is represented by a small positive voltage, shown by reference line 38, and black by a larger positive voltage, shown by reference line 40. In the example shown, video line 32c is at a medium gray level most of the way across with a blacker portion in the middle.

To produce a color picture on the screen, the signal controls a triple set of electron beams that scan across the surface of the screen from left to right and down the screen from top to bottom. At the end of each scan line, the beam is swept rapidly back to the left during a process called horizontal retrace to scan the next line. When the beam reaches the bottom of the screen, the beam is swept rapidly back to the top during a process called vertical retrace.

The end of each video line 32 is followed by a horizontal blanking pulse 36, which functions to turn-off electron beam during a horizontal retrace. If a video line 32 occurs at the bottom of the screen, then the horizontal blanking pulse 36 is replaced by a vertical blanking pulse 42 that has a longer blanking interval, as shown in Figure lb. The vertical blanking pulse 42 comprises a series of horizontal blanking pulses 36 that provide enough time to allow a display device's electron beam to be repositioned at the top of the display screen. Data may be encoded into the vertical blanking pulses 42, such a close captioning information in the case of television broadcasts.

Figure 2 is a block diagram illustrating a conventional digital baseband signal. As is well known to one with ordinary skill in the art, the digital baseband signal 30b is similar to an analog baseband signal 30a in that a digital baseband signal 30b also comprises a series of values that control the chrominance and luminance for N pixels. In a digital baseband signal 30b, however, those values are discrete, "1" (on) and "0" (off), rather than continuous as in an analog baseband signal 30a.

The values in both analog and digital baseband signals 30a and 30b may be based on a red, green, and blue (RGB) color space, or based on what is referred to as a YUV color space, which control how the information will appear when it is displayed and/or printed. The letters Y, U, and V are not abbreviations, but commonly used letters that define the luminance or brightness (Y) of a color, and the color content or chrominance (UV). Figure 3 is a block diagram illustrating two examples of electronic devices that output digital baseband signals 30b; notebook computers 50a and personal digital assistants (PDAs) 50b. Both devices (hereinafter referred to as digital devices 50) enable a user to input and store information from an input device, such as a keyboard 52a or an electronic pen 52b. Both devices 50 also include a display screen 54a and 54b for displaying information that is stored in the device or that has been received from a network, such as the Internet. Due to the size of the devices 50, the display screen 54 is often small and difficult to read. Therefore, it is often desirable to display the information on a device that has a larger screen, such as on a television, for example.

Figure 4 is a block diagram of a conventional television. The television 70 includes a power supply 72 that receives power from a power cord 74 that includes two wires 74a and 74b. If the power cord 74 includes a grounded plug, then the power cord 74 also includes a ground wire (not shown). The television 70 further includes a tuner 76 (channel decoder) for decoding channel encoded information, and a screen 80 for displaying the received information. An external coaxial cable 82 is often coupled to the tuner 76 for supplying channel encoding information in the form of analog radio frequency (RF) signals.

The electrical power signal transmitted over the power cord 74 is typically supplied at either 110 volts (U.S.) or 220 volts (European), and modulated at either 50 Hz or 60 Hz. The television tuner 76, in contrast, operates at 5 to 12 volts D.C. The power supply 72 takes the 110 or 220 volts from the power cord 74 and converts it to a voltage that is compatible with the tuner 76. The power supply 72 also includes rejection circuity that is designed to reject normal interferences (e.g. 50 to 120 Hz) that exist with the power delivery system.

Before the information encoded in an analog or digital baseband signal 30a and 30b (hereinafter referred to as baseband signal 30) can be displayed on the television 70, the baseband signal 30 must first be converted into a television compatible RF modulated signal.

A traditional method for displaying computer images on a television 70 is to convert the computer signals into baseband video and/or audio signals and using an analog RF modulator to modulate the digital signal up to the frequency of the RF signal. Unfortunately, modulating computer signals into a RF signal is problematic because a unified RF standard does not exist. Many different RF standards exist throughout the world because countries designate different modulation frequencies and modulation methods to RF signals. The design of RF modulators is therefore specific to both a particular television standard as well as to the designated modulation frequency and modulation method of the appropriate country. For example, a RF converter designed for the U.S. will not work in Japan even through the both the U.S. and Japan use the same television standard.

After a baseband signal 30 from an electronic device has been converted into an RF signal, the RF signal must be distributed to the television 70 in order to display information. Traditional methods require a physical connection between the television 70 set and a coaxial cable 82 in order to distribute the RF signal because the coaxial cable 82 is fabricated by surrounding a center conductor with a grounded metal braid. This metal braid is specifically designed to shield the conductor from external electronic influence. It is therefore not practical to inject a signal into the coaxial cable 82 without first making physical contact to the inside conductor of the cable.

The most convenient method for distributing an RF signal to a television 70 is to simply plug the RF signal into a television 70 set that is equipped with a RF input. The RF signal may be distributed to the television 70 by disconnecting the coaxial cable 82 and then connecting an RF adapter between the television 70 and the coaxial cable 82.

This method is acceptable for semi-permanent installations, such as the home, but has significant limitations in other situations, such as a hotel room where the television 70 may be bolted to the wall. It is impractical and sometimes impossible for the average traveler to carry the necessary tools to disconnect the existing coaxial cable 82 from a hotel television 70 in order to connect a RF modulated signal from an electronic device to the television 70 via an RF adapter.

Accordingly, what is needed is an improved system and method for both converting baseband signals into a television compatible RF signal and for then distributing the RF signal to the television. The present invention addresses such a need.

SUMMARY OF THE INVENTION

The present invention provides a radio frequency (RF) converter/distributor for converting a baseband signal into a RF signal and for distributing the RF signal to an input device, such as a television, that receives a power signal. The RF converter/distributor device includes an input for receiving the baseband signal, a RF modulator coupled to the baseband signal for converting the baseband signal into a RF signal, and a RF distributor coupled to the RF signal for inducing the RF signal onto the power signal for reception by the input device. In addition, the RF modulator is digital and programmable such that the RF signal is selectable for compatibility with numerous RF standards.

According to the system and method disclosed herein, the present invention enables a notebook computer to display information directly on a television by converting and transmitting a RF signal directly through the television's power cord and into the television, eliminating the need to disconnect the television's coaxial cable. In addition, the programmable RF modulator allows the notebook computer to operate with any country's television standard.

BRIEF DESCRIPTION OF THE DRAWINGS Figures la and lb are a block diagrams depicting a conventional analog baseband signal.

Figure 2 is a block diagram illustrating a conventional digital baseband signal.

Figure 3 is a block diagram illustrating two examples of electronic devices that output digital baseband signals.

Figure 4 is a block diagram of a conventional television. Figure 5 is a block diagram illustrating a RF converter/distributor in accordance with the present invention.

Figure 6 is a block diagram depicting the components of the digital RF modulator.

Figure 7 is a block diagram illustrating a non-intrusive embodiment of the RF distributor.

Figure 8 is a block diagram illustrating the intrusive embodiment of the RF distributor. Figure 9 is a block diagram depicting an intrusive single-ended wire transformer coupling.

Figure 10 is a block diagram depicting an intrusive double-ended transformer coupling.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to RF conversion and distribution. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein.

The present invention provides a system and method for converting baseband signals 30 into a television compatible RF modulated composite signal and for distributing the RF signal to a television 70. More specifically, the present invention provides a digital RF modulator that can be programmed to convert a baseband signal 30 into a standard RF modulated signal of any given frequency. The present invention further provides a system and method for distributing the RF modulated signal to a video input device, such as a television 70 or VCR over the power signal sent to the input device, rather than through a coaxial cable. To more particularly describe the present invention, refer now to

Figure 5 depicting a block diagram of one embodiment of such a system.

Figure 5 is a block diagram illustrating a RF converter/distributor 100 in accordance with the present invention. The RF converter/distributor 100 includes an input 102 for a baseband signal 30, a digital RF modulator 104 coupled to the input 102, and a RF distributor 106 coupled to both the digital RF modulator 104 and to a power cord 108 of an input device 110, such as a standard television. Hereinafter, the input device 110 will be referred to as a television, but may also include any device that includes a tuner, such as VCRs and FM radios (for receiving audio signals), for example. The baseband signal 30 may be either analog or digital and includes video and/or audio information. In one aspect of the present invention, the digital RF modulator 104 is programmable to convert the baseband signal 30 into a RF signal 114 of the desired frequency. The RF signal 114 is then input to the RF distributor 106 for distribution to the television 110. In another aspect of the present invention, the RF distributor 106 distributes the RF signal 114 to the television 110 by inducing the RF signal 114 onto the 50 Hz or 60 Hz power signal at the appropriate voltage within the television power cord 108. For example, channel 3 in the U.S. is 50 to 70 MHZ, but may vary worldwide. Therefore, in order to send the RF signal 114 for channel 3 to the television 110, the RF distributor would first modulate the baseband signal 30 up to 50 MHZ and then induce the 50 MHZ RF signal onto the 60 Hz power signal in the power cord 108.

Modulating the RF signal 114 onto the power signal within the power cord 108 of the television 110 transforms the power cord 108 into a signal carrier. The rejection circuity in the television 110 will fail to reject the RF signal 114 because the RF signal 114 surpasses the 60 to 120 Hz interference threshold. As a result of the process, the power supply outputs a 5 to 12 volt D.C. signal that carries the RF modulated signal to the television tuner 76 (Figure 4).

Consequently, the television power supply 72 acts as an antenna and radiates the RF signal 114 throughout the internal circuitry of the television 110 where it can be picked up by the television tuner 76 and demodulated as a standard television signal. After the tuner 76 receives the RF signal 114, the video information in the RF signal 114 originating from the baseband signal 30 is displayed on the television screen 80. If the baseband signal 30 includes audio, then the audio from the RF signal 114 will be played through the television speakers. Thus, the RF distributor 106 acts as an RF adapter for the television 110, but without the requirement that the user disconnect the existing coaxial cable 82. Furthermore, the RF distributor 106 is capable of delivering both digital computer signals to the television 110, as well as analog signals from a video recorder, for example. One with ordinary skill in the art will appreciate that this method can also work with DC power supplies such as battery powered televisions 110, VCRs, and FM radios.

Figure 6 is a block diagram depicting the components of the digital RF modulator 104. The digital RF modulator 104 includes a video component 130, an audio component 132, a combiner 134, a digital-to-analog converter 136, and a controller 138.

The input to the digital RF modulator 104 is a video portion 140 of the baseband signal 30, an optional audio portion 142 of the baseband signal 30

(typically stereo left and right), and an optional data portion 144 of the baseband signal 30. If the input baseband signal 30 is analog, rather than digital, then the analog baseband signal 30 is converted into a digital signal by an analog-to-digital converter (not shown) before being input to the video and audio components 130 and 132 of the digital RF modulator 104.

The video component 130 converts the video portion 140 of the baseband signal 30 into an intermediate frequency (IF) video signal 148 and then converts the IF video signal 148 into a RF video signal 150. This is done through the use an encoder 152, an intermediate frequency component 154, a local oscillator 156, and an up-converter 158.

The encoder 152 includes a luminance processor 160 and a chrominance processor 162. If the baseband signal 30 is based on the RGB color space, then the encoder 152 first converts the baseband signal 30 into a YUV color space that includes luminance and color components. The chrominance processor bandli its the color components of the YUV-based signal, and then modulates the color components using a sine and cosine quadrature method in order to combine the color component into a single composite chrominance signal (not shown). The encoder 152 then combines the luminance signal from the luminance processor 160 and the composite chrominance signal from the chrominance processor 162 into a composite video signal 164.

The composite video signal 164 is then input to the intermediate frequency component 154. The intermediate frequency component 154 includes an oscillator 166 and a modulator 168 for modulating the composite video signal 164 into an IF video signal 148. In a preferred embodiment, the intermediate frequency component 154 performs amplitude modulation on the video signal

164.

The local oscillator 156 and the up-converter 158 heterodynes the IF video signal 148 up to an appropriate radio frequency (RF) frequency (typically channels 3 or 4 in the U.S.). The output of the video component 130 is a RF video signal 150.

The audio component 132 modulates the audio and data portions 142 and 144 of the baseband signal 30. The audio portion 142 typically includes stereo left and right signals. The audio component includes a protocol processor 170, an intermediate frequency component 172, a local oscillator 174, and an up- converter 176.

The protocol processor 170 includes a stereo and surround processor 178 and a second audio program 180 for processing the stereo left and right signals from the baseband audio portion 142. The protocol processor 170 also includes an auxiliary data processor 182 for processing the data portion 144 of the baseband signal 30.

The output from the protocol processor 170 is a composite audio signal 184, which is input into the intermediate frequency component 172. The intermediate frequency component 172 includes an oscillator 185 and a modulator 186 for modulating the left and right audio portions 142 and the data portion 144 of the baseband signal 30 into an IF audio signal 188. In a preferred embodiment, the intermediate frequency component 172 performs frequency modulation on the IF audio signal 188.

The local oscillator 174 and the up-converter 176 heterodynes the IF video signal 188 up to the appropriate radio frequency (RF) frequency. The output of the video component 130 is an RF audio signal 190.

The combiner 134 combines the RF video signal 150 from the video component 130 and the RF audio signal 190 from the audio component 132 into a single RF signal 192. The combiner 134 could be implemented as either and adder or a weighted summation function. The combiner 134 is sometimes referred to as a weighted summation function because the power level at which the RF audio signal 190 is output from is different that the power that the RF video signal 150 is output. In another preferred embodiment, the RF video signal 150 and the RF audio signal 190 are combined by the combiner 134 before they are up-converted by the up-converters 158 and 176. The single RF signal 192 is then input into the digital-to-analog converter 136, where the digital RF signal 192 is converted into an analog RF signal 114, and then amplified by an amplifier (not shown) before distribution.

According to the present invention, the functions of the video component 130 and the audio components 132s of the digital RF modulator 104 are programmable through the controller 138. The controller 138 is coupled to both the video component 130 and the audio component 132 and controls all the variables therein that are selectable. For example, the controller 138 controls the sets of frequencies that the IF signals 148 and 188 may be modulated to by the intermediate frequency components, and also controls the frequencies to which the up-converters 158 and 176 convert the IF signals 148 and 188.

The controller 138 is preferably a microprocessor, but may also be implemented as a dip switch or an erasable programmable read only memory (EPROM), for instance. In addition, the digital RF modulator 104 may be automatically programmed when incorporated into a cable set-top box, for example. When the cable signal is input into the box, the controller 138 may detect the incoming RF frequency and modulate an input baseband signal 30 to match the incoming RF frequency.

Referring again to Figure 5, the RF distributor 106 may be implemented according to one of three embodiments. In the first preferred embodiment, the

RF distributor 106 is implemented as a non-intrusive device, which induces the RF signal onto the power signal within the television power cord.

In the second preferred embodiment, the RF distributor is implemented as an intrusive device, which also induces the RF signal onto the power signal within the television power cord.

In the third preferred embodiment, the RF distributor is also implemented as an intrusive device, but induces the RF signal onto the power signal within the alternating current (AC) interface of the surrounding structure.

Figure 7 is a block diagram illustrating the non-intrusive embodiment of the RF distributor 200. In response to an input RF signal 202, the RF distributor

200 induces the RF signal 202 onto the power signal within the television power cord 108 using a free space coupling mechanism, rather than a direct physical connection. The free space coupling mechanism comprises a single wire 204 that is inductively coupled around the two wires of the power cord 108. Other electromagnetic coupling devices may also be used instead of the single wire 204, such as a ferrite bead, an inductive parallel wire coupling, and a ferro magnetic material, for instance.

In some instances, the non-intrusive RF distributor 200 may not provide a modulated RF signal that results in stable television reception since the RF distributor 200 is a free space coupling device. The television reception may be improved through the use of the intrusive embodiment of the RF distributor, as shown in Figure 8.

Figure 8 is a block diagram illustrating the second preferred embodiment of the RF distributor 210, which is implemented as an intrusive RF distributor 210. Rather than using a free space coupling mechanism as in the non-intrusive RF distributor, the intrusive RF distributor 210 makes a direct connection to the television power 108 cord.

The intrusive RF distributor 210 includes an electrical outlet 212, a RF input 214, and a conventional power cord 216. An RF signal 202 from the digital RF modulator 104 or other source is coupled to the RF input 214. The RF input 214 is preferably implemented as an F-connector, but could also include an infrared input device. If the RF signal 202 is provided by the digital RF modulator 104, then both the digital RF modulator 104 and the RF distributor 210 may be included in the same housing, in which case the external RF input 214 would be replaced by the input 102 for a baseband signal 30, as shown in Figure 5. The television power cord 108 plugs into the electrical outlet 212 of the intrusive RF distributor 210, while the RF distributor power cord 216 plugs into a wall outlet. In this embodiment, the RF distributor power cord 216 effectively acts as an extension of the television power cord 108 by transferring a power signal from the wall outlet to the television power cord 108. The intrusive RF distributor 210 induces the RF signal 202 onto the power signal through the use of a transformer coupling.

In one example implementation, a single-ended wire transformer coupling is used. In a second example implementation, a double-ended wire transformer coupling is used.

Figure 9 is a block diagram depicting the intrusive RF distributor 210' implemented using a single-ended wire transformer coupling 220. In the single- ended wire example, one wire from the television power cord 108 is passed through the RF distributor 210' to a corresponding wire in the RF distributor power cord 216. The second wire from the television power cord 108 is coupled to the corresponding wire in the RF distributor power cord 216 through a transformer 220 formed by two coils 220a and 220b. The RF signal 202 input into the intrusive RF distributor 210' is sent through the first coil 220a and the resultant flux on the first coil 220a induces a field on the second coil 220b that includes the modulated RF signal 202. The modulated RF signal 202 is then passed from the second coil 220b to the television 110 via the television plug and the corresponding wire in the television power cord 108.

The transformer 220 may either be an air core transformer where the space between the coils is filled with air, or the transformer 220 may be an iron core transformer where the space between the coils 220a and 220b is filled with iron. Figure 10 is a block diagram depicting the intrusive RF distributor 210" implemented using a double-ended transformer coupling. In the double-ended wire example, each wire in the television power cord 108 is coupled to the corresponding wire in the RF distributor power cord 216 through a respective transformer 230 and 232. A positive RF signal 202 from the intrusive RF distributor 210" is induced on one of the television power cord 108 wires by transformer 230. And a negative RF signal 202 from the RF distributor 210 is induced on the second television power cord wire by transformer 232. Referring again to Figure 4, the RF signal 202 is then passed to the television power supply 72 via the power signal, and onto the television tuner 76 where it is received as a television signal.

This RF converter/distributor of the present invention has a number of significant advantages. One advantage is that digital encoding of the digital RF modulator 104 is programmable, allowing a single device, such as a personal digital assistant or notebook computer, to operate with numerous countries and/or television standards. The size of the digital RF modulator 104 is also significantly smaller than conventional modulators, allowing use in small portable devices. Another advantage is that the RF distributor 106 can be used on any input RF signal 202, whether it originated from a computer or a camcorder.

Referring now to Figure 11, a block diagram depicting the third embodiment of the RF distributor 240 is shown. The RF distributor 240 is also implemented as an intrusive device that operates in conjunction with the surrounding structure's alternating current AC interface 242, which is accessed by wall outlets 244. The RF distributor 240, however, plugs directly into the wall outlet 244, rather than using a power cord. An RF signal 246 from the digital RF modulator 104 or other source is coupled to an RF input 248. The RF signal 246 is then induced into the power signal within the AC interface 242 and distributed throughout the structure of the surrounding building using the building's internal AC wiring. The RF signal may then be accessed from any wall outlet 244 within that building. Figure 12 is a block diagram illustrating an RF converter/ distributor 250 in which a digital RF modulator 104 of Figure 5 is included in the same housing as the third embodiment of the intrusive RF distributor 240 (where like components of Fig. 5 have like reference numerals).

The RF converter/distributor 250 includes an input 102 for a baseband signal 30. a digital RF modulator 104 coupled to a baseband input 102, and a RF distributor 240 coupled an AC interface 242 via a wall outlet (not shown). A television 110 or other type of input device is also connected to the AC interface 242 via a power cord 108.

The baseband signal 30 may be input from any digital device, such as a desktop personal computer for example, which may located in the same room as the television 110 or in a separate room. The digital RF modulator 104 converts the baseband signal 30 into a RF signal 114 of the desired frequency, and the RF signal 114 is then input to the RF distributor 240 for distribution over the power signal within the AC interface 242.

As described above with reference to Figure 5, the RF signal that is modulated onto the AC power signal is received by the television power cord 108. The power signal and the modulated RF signal are passed to the television's power supply and on to the television tuner 76 (Figure 4), where the RF signal is then demodulated and displayed as a standard television signal. Providing the RF modulated signal over the AC interface in accordance with the present invention enables a user to display images on a television from a computer that is located in a different room over a single AC wire interface. The present invention also provides a system and method that allows the user to interface with the computer from the same room as the television in order to control what infoπnation is displayed on the television.

Figure 13 is a block diagram illustrating a system 600 for remote data transmission and control of distributed input devices over an AC interface 602. The system illustriously includes a digital device, such as a computer 604, a device controller, such as a keyboard 606 for controlling the computer 604, and an input device, such as a television 608. The computer 604, the television 608, and the keyboard 606 are all coupled to the AC interface 602.

In applications where the system 600 is located in a home, the computer 604 may be located in a room separate from the television 608 and the keyboard 606. Although the device controller is shown as a keyboard 606, any device controller capable of controlling a computer is also suitable, such as a pointing device (e.g. a mouse), or a microphone for voice commands for instance.

According to the present invention a transmitter 610 operating independently of the RF converter/distributor 250 is coupled between the keyboard 606 and the AC interface 602, and a receiver 620 is coupled between the AC interface 602 and the computer 604.

The transmitter 610 includes a modulator 612, a frequency converter 614, and a RF distributor 616. The transmitter 610 also includes a port (not shown) for providing power to the keyboard 606. In response to the user typing commands, the keyboard 606 generates keystroke data. The modulator 612 and the frequency converter 614 modulate the keystroke data into a RF data signal

618, which is then induced onto the power signal within the AC interface 602 by the RF distributor 616. In a preferred embodiment, the RF data signal 618 is modulated at a frequency above or below the frequency threshold of the television 608, such that the rejection circuitry inside the television 608 will reject the RF data signal 618.

The receiver 620 coupled between the AC interface 602 and the computer 604 includes a transformer 622 and a demodulator 624. The transformer 622 receives the RF data signal 618 from the AC interface 602 and drops the voltage of the signal down to a level compatible with the computer 604. The transformer 622 then passes the RF data signal 618 to the demodulator 624 where the signal is demodulated back into keyboard data and sent to the computer 604. The computer 604 processes the commands and generates baseband signals accordingly.

An RF converter/distributor 250 is coupled to the computer 604 as explained with reference to Figure 12. The RF converter/distributor 250 receives the baseband signals from the computer 604 and modulates the signals into an RF signal. The RF modulated signal is then induced onto the power signal within the AC interface 602, where it is received by the television, demodulated and displayed.

As will be appreciated by those having ordinary skill in the art, the system 600 may have any number of televisions 608, any number of computers 604 and corresponding receivers, and any number of keyboards 606 and corresponding transmitters 610. For example, in an airport application, any number of keyboards could be used to send commands to backroom computers for controlling the information displayed on departure and arrival monitors.

A system and method for radio frequency conversion and distribution has been disclosed. Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.

Claims

What is claimed is:

1 A radio frequency (RF) converter/distributor for operation with an input device, the input device receiving power from a power signal, the RF converter/distributor comprising: an input for receiving a baseband signal; an RF modulator coupled to the baseband signal for converting the baseband signal into a RF signal; and a RF distributor coupled to the RF signal for inducing the RF signal onto the power signal for reception by the input device.

2 The invention of claim 1 wherein the RF modulator comprises is a programmable digital RF modulator such that the RF signal is selectable for compatibility with a plurality of RF standards.

3 The invention of claim 2 wherein the baseband signal includes a video portion, the digital RF modulator further including a video processing component for modulating the video portion of the baseband signal into a RF video signal.

4 The invention of claim 3 wherein the baseband signal includes an audio portion, the digital RF modulator further including an audio processing component for modulating the audio portion of the baseband signal into a RF audio signal.

5 The invention of claim 4 wherein the digital RF modulator further includes a controller for controlling the modulating functions of the video and audio components.

6 The invention of claim 5 wherein the digital RF modulator further includes a combiner for combining the RF video signal and the RF audio signal into the RF signal.

7 The invention of claim 6 wherein the digital RF modulator further includes a digital-to-analog converter for converting the RF signal from a digital signal to an analog signal.

8 The invention of claim 7 wherein the baseband signal is a digital baseband signal based on a Red Green Blue color space, and wherein the video component converts the Red Green Blue color space of the digital baseband signal into a YUV color space.

9 The invention of claim 7 wherein the baseband signal is an audio baseband signal, and wherein the RF converter/distributor device further includes an analog-to-digital converter for converting the analog baseband signal into a digital baseband signal.

10 The invention of claim 1 wherein the RF distributor induces the RF signal onto the power signal using a non-intrusive free-space coupling mechanism.

11 The invention of claim 10 wherein input device receives the power signal from a power cord, and wherein the non-intrusive coupling mechanism comprises a single-wire that is inductively coupled around the power cord.

12 The invention of claim 1 wherein the RF distributor induces the RF signal onto the power signal using an intrusive coupling mechanism.

13 The invention of claim 12 wherein the intrusive coupling mechanism is a single-wire transformer.

14 The invention of claim 13 wherein the intrusive coupling mechanism is a double-wire transformer. 15 The invention of claim 14 wherein the power signal is within an alternating current (AC) interface.

16 A method for converting and distributing a radio frequency (RF) signal to an input device, the input device receiving power from a power signal, the method comprising the steps of:

(a) receiving a baseband signal;

(b) converting the baseband signal into a RF signal; and

(c) inducing the RF signal onto the power signal for reception by the input device.

17 The invention of claim 16 wherein step (b) further includes the step of:

(bl) programmably converting the baseband signal into a RF signal such that the RF signal is selectable for comparability with a plurality of RF standards.

18 The invention of claim 17 wherein the baseband signal includes a video portion, step (b) further including the step of: (b2) modulating the video portion of the baseband signal into a

RF video signal.

19 The invention of claim 18 wherein the baseband signal includes an audio portion, step (b) further including the step of: (b3) modulating the audio portion of the baseband signal into a

RF audio signal.

20 The invention of claim 19 wherein step (b) further includes the step of: (b4) controlling the modulating functions of the video and audio components. 21 The invention of claim 20 wherein step (b) further includes the step of:

(b5) combining the RF video signal and the RF audio signal into the RF signal.

22 The invention of claim 21 wherein step (b) further includes the step of:

(b6) converting the RF signal from a digital signal to analog signal.

23 The invention of claim 22 wherein the baseband signal is a digital baseband signal based on a Red Green Blue color space, and wherein step (b) further includes the step of:

(b7) converting the Red Green Blue color space of the digital baseband signal into a YUV color space.

24 The invention of claim 22 wherein the baseband signal is an audio baseband signal, and wherein step (b) further includes the step of:

(b8) converting the analog baseband signal into a digital baseband signal.

25 The invention of claim 16 wherein step (c) further includes the step of:

(cl) inducing the RF signal onto the power signal using a non- intrusive free-space coupling mechanism.

26 The invention of claim 25 wherein the input device receives the power signal from a power cord, and wherein step (c) further includes the step of: (c2) inductively coupling a single-wire around the power cord.

27 The invention of claim 16 wherein step (c) further includes the step of:

(cl) inducing the RF signal onto the power signal using an intrusive coupling mechanism.

28 The invention of claim 27 wherein input device receives the power signal from a power cord, and wherein step (c) further includes the step of: (c2) coupling a single-wire transformer to the power cord.

29 The invention of claim 27 wherein step (c) further includes the step of:

(c2) coupling a double-wire transformer to the power cord.

30 The invention of claim 16 wherein step (c) further includes the step of: (cl) inducing the RF signal onto the power signal within an alternating current (AC) interface.

31 A digital radio frequency (RF) modulator comprising: an input for receiving a baseband signal, the baseband signal including a video portion and an audio portion; a video processing component for converting the video portion of the baseband signal into an intermediate frequency (IF) video signal and for converting the IF video signal into a RF video signal; an audio processing component for converting the audio portion of the baseband signal into an intermediate frequency (IF) audio signal and for converting the IF audio signal into a RF audio signal; a combiner for combining the RF video signal and the RF audio signal into a digital RF signal; a digital-to-analog converter for converting the digital RF signal into an analog RF signal; and a controller coupled to both of the video and audio components for controlling the modulating functions of the video and audio components such that the signal frequency of the digital RF signal is selectable from among a plurality of different RF signal standards.

32 The invention of claim 31 wherein the video portion of the baseband signal comprises luminance components and chrominance components, and wherein the video processing component further includes, an encoder coupled to the video portion for combining the luminance components and the chrominance components into a composite video signal, an intermediate frequency component responsive to the composite video signal for modulating the composite video signal into the IF video signal, and a local oscillator coupled to an up-converter for heterodyning the IF video signal up to a selected radio frequency to generate the RF video signal.

33 The invention of claim 32 wherein the baseband signal is based on a Red Green Blue color space, and wherein the encoder converts the Red Green

Blue color space of the baseband signal into a YUV color space.

34 The invention of claim 33 wherein the encoder further includes a chrominance processor for bandlimiting the chrominance components and for modulating the chrominance components using a sine and cosine quadrature method.

35 The invention of claim 34 wherein the intermediate frequency component modulates the composite video signal into the IF video signal using an oscillator and a modulator.

36 The invention of claim 35 wherein the intermediate frequency component performs amplitude modulation on the video signal.

37 The invention of claim 31 wherein the audio component includes, a protocol processor for processing the audio portion of the baseband signal to generate an audio signal; an intermediate frequency component responsive to the audio signal for modulating the audio signal into the IF audio signal, and a local oscillator coupled to an up-converter for heterodyning the IF audio signal up to a selected radio frequency to generate the RF audio signal.

38 The invention of claim 37 wherein the audio portion includes a first and second audio portion, and wherein the protocol processor further includes a stereo and surround processor for processing the first audio portion, and a second audio program for processing the second audio portion.

39 The invention of claim 38 wherein the baseband signal further includes a data portion, and wherein the protocol processor further includes an auxiliary data processor for processing the data portions of the baseband signal.

40 A RF distributor for distributing a RF signal to an input device having internal circuitry including a channel decoder for receiving a plurality of standard radio frequency (RF) signals, and a power supply for receiving an external power signal, the RF distributor comprising: an input for receiving a RF signal; and inducing means responsive to the RF input for inducing the RF signal onto the power signal such that in response to the power signal reaching the power supply, the RF signal is radiated throughout the internal circuitiy of the input device wherein the RF signal is received by the channel decoder and demodulated as one of the plurality of standard RF signals.

41 The invention of claim 40 wherein the inducing means is a non- intrusive free-space coupling mechanism.

42 The invention of claim 41 wherein input device receives the external power signal from a power cord, and wherein the non-intrusive free- space coupling mechanism comprises a single-wire that is inductively coupled around the power cord. 43 The invention of claim 42 wherein the input device is a television.

44 The invention of claim 42 wherein the input device is a VCR.

45 The invention of claim 42 wherein the input device is a FM radio.

46 The invention of claim 42 wherein the input for receiving the RF signal is an F-connector.

47 The invention of claim 42 wherein the input for receiving the RF signal is an infrared device.

48 The invention of claim 40 wherein the inducing means is an intrusive coupling mechanism.

49 The invention of claim 48 wherein the intrusive coupling mechanism is a single-wire transformer.

50 The invention of claim 48 wherein the intrusive coupling mechanism is a double-wire transformer.

51 The invention of claim 48 wherein the input device is a television.

52 The invention of claim 48 wherein the input device is a VCR.

53 The invention of claim 48 wherein the input device is a FM radio.

54 The invention of claim 48 wherein the input for receiving the RF signal is an F-connector.

55 The invention of claim 48 wherein the input for receiving the RF signal is an infrared device. 56 A system for remote access and remote viewing of graphics data over an alternating current (AC) interface, the system comprising: a digital device for providing graphics data; an RF converter/distributor coupled between AC interface and the digital device for modulating the graphics data into a first radio frequency (RF) signal and for inducing the first RF signal onto the AC interface; a digital device controller for allowing a user to operate the digital device, wherein in response to user input, the digital device controller generates control data; a transmitter operating independently of the RF converter/distributor coupled between AC interface and the digital device controller for modulating the control data into a second RF signal and for inducing the second RF signal onto the AC interface; and a receiver operating independently of the RF converter/distributor coupled between AC interface and the digital device for receiving and demodulating the second RF signal, and for providing the control data to the digital device.

57 The invention of 56 further including: an input device coupled to the AC interface for displaying radio frequency (RF) signals, wherein the input device reveives and displays the first RF signal from the the AC interface, and rejects the second RF signal.

58 The invention of claim 57 wherein the input device comprises a television.

59 The invention of claim 58 wherein the digital device comprises a computer.

60 The invention of claim 59 wherein the digital device controller includes a keyboard.

61 The invention of claim 60 wherein the digital device controller includes a pointing device.