MXPA97004630A - Improvement of resincronisation of simultaneous broadcasting, using the gloft placement system - Google Patents

Abstract

In a radio frequency multiple site transmission system R.F. of simultaneous radial transmission, the data provided through inter-site communications links (L1, L2, etc.) from a control point to the transmitting sites of R.F. it exhibits a skewed random time delay because the multi-phase modems retrieve the clock signals of an arbitrary phase of the multiple phases. The output data streams of the modems are temporarily stored in the intermediate memory sites for temporary alignment for transmission of R.F. simultaneous. The buffers at each site are periodically resynchronized on a continuous basis by a universal "resinc" circuit to maintain optimal operation of the simultaneous broadcasting system. A data clock reference of 9600 bps and a low frequency data signal (timing) to perform a periodic "resinc" operation are derived separately from a common satellite reference signal acquired using a GPS receiver (satellite receiver). global positioning) in each site of the simultaneous broadcasting system. A resynchronization operation on a continuous basis is performed periodically separately by each simulcasting system and the distributed multisite broadcasting data stream is aligned using the resynchronization reference tone derived from the GPS signal received.

Description

"IMPROVEMENT OF RESINCRONISATION OF SIMULTANEOUS BROADCASTING, USING THE GLOBAL PLACEMENT SYSTEM" REFERENCES TO APPLICATIONS AND RELATED PATENTS This application is to a certain degree related to the commonly assigned US Patent Number 5,172,396 in favor of Rose and others, issued December 15, 1992, called "Public Service Trunking Simulcast System" and with the US Patent Number 4,903,321 granted to Hall and others. , issued on February 20, 1990, called "Radio Trunking Fault Detection System". This request is also to some extent related to the following co-pending assigned applications: serial number 07 / 824,123 Brown and others, called "Self Correction Of PST Simulcast System Timing", filed on January 22, 1992 (Attorney's Number 46-444; Customer Reference Number 45-MR-664) and serial number 07 / 906,438 by Thomas A. Brown entitled "Control Channel Timing Detection and Self Correction for Digitally Trunked Simulcast Radio Communications System", filed on June 30, 1992 (Law Number of the Attorney 46-594, Customer Reference Number 45-MR-711). The expositions of each of the aforementioned patents and applications are incorporated by reference as expressly indicated herein.

FIELD OF THE INVENTION This invention relates to radio frequency (RF) signal transmission systems, and in particular, to "simultaneous radial transmission" systems to provide simultaneous transmission of the same information by two or more RF transmitters placed separately. More particularly, the invention relates to an improved method and apparatus for generating timed "resin" (resynchronization) reference signals from simultaneous broadcasting in each transmitter site, to maintain the coherence of transmissions.

BACKGROUND AND UNDERSTAND OF THE INVENTION As is well known, due to FCC power limitations, geographic and / or other factors, it is sometimes possible for a single RF transmitting site to provide appropriate coverage to a large area of desired coverage. For example, government agencies commonly use land mobile radio communications systems to provide communications between a main office and the various mobile and portable radio users traveling through the jurisdiction of the government entity. In some cases, the geographic area of the jurisdiction is so large that it is not possible for a single terrestrial-based RF transmitter site to cover it. Even when the effective radial power of the single transmission site was large enough to cover the entire area, users in the areas located or bordered could receive only questionable service due to the nature of the "site line" of the VHF transmsiones and / o due to geographic obstructions (mountains, bridges, constructions and curvature of the earth) interposed between the single transmitter site and several bordering locations within the coverage area. A known way to expand the coverage area is to provide multiple simultaneous "radial" transmission sites. In order to simplify the operation of the mobile radio and preserve the radiofrequency spectrum, these "simultaneous radial transmission" RF transmission sites all transmit essentially identical signals for essentially identical times in essentially identical radio frequencies. This "simultaneous radio transmission" limits the control that exceeds the calculated flow and other complexities associated with carrying out the "deliveries" from one coverage area of the RF transmitting site to another as is common, for example, in the systems of cellular and "multiple site" RF communications. The so-called RF repeater systems of "Digitally linked simultaneous radio transmission" are generally known. Below is a list (which is by no means exhaustive) of prior documents describing the various aspects of simultaneous radio transmission of RF transmission and related matters: U.S. Patent No. 5,172,396 issued to Rose et al., U.S. Patent Number 4,903,321, issued to Hall and others; U.S. Patent Number 4,696,052 issued to Breeden; U.S. Patent Number 4,696,051 granted to Breeden; US Patent Number 5,245,634 granted to Averbuch; U.S. Patent No. 5,287,550 issued to Fenell et al .; US Patent Number 4,782,499 granted to Clendening; U.S. Patent Number 5,052,028 issued to Zwack; U.S. Patent Number 4,570,265 issued to Thro; U.S. Patent Number 4,516,269 granted to Krinock; North American Patent Number 4,475,246 granted to Batlivala and others; U.S. Patent No. 4,317,220 issued to Martin; U.S. Patent No. 4,972,410 issued to Cohen et al .; U.S. Patent Number 4,608,699 granted to Batlivala and others; U.S. Patent Number 4,918,437 granted to Jasinski and others; North American Patent Number 4,578,815 granted to Persinott; U.S. Patent No. 5,003,617 issued to Epsom et al .; US Patent Number 4,939,746 granted to Childress; US Patent Number 4,903,262 granted to Dissosway and others; U.S. Patent No. 4,926,496 issued to Cole and others; US Patent Number 4,968,966 granted to Jasinski and others; U.S. Patent Number 3,902,161 issued to Kiowaski et al .; U.S. Patent No. 4,218,654 issued to Ogawa et al .; U.S. Patent Number 4,255,815 issued to Osborn; U.S. Patent No. 4,411,007 issued to Rodman et al .; U.S. Patent Number 4,414,661 granted to Karlstrom; U.S. Patent No. 4,472,802 issued to Pin et al .; U.S. Patent Number 4,597,105 granted to Freeburg; and Japanese Patent Laid-Open No. 61-107826. U.S. Patent No. 5,172,396, issued December 15, 1992, in favor of Rose et al., Entitled "Public Services Trunking Simulcast.

System ", discloses a radio-linked simultaneous radio transmission system having remote site and control site architectures that include timeliness timing of RF transmission that are related to the exemplary embodiment preferred at present. The patent American Number 4,903,321 issued February 20, 1990 in favor of Hall and others, entitled "Radio Trunking Fault Detection System ", discloses a linked radio repeater system having a radio frequency repeater site architecture that includes failure and call-and-fail test features that are somewhat related to the present invention, these patents are both commonly assigned to the concessionaire of the present invention and both are incorporated by reference herein Even though simultaneous radial transmission, therefore, provides distinct advantages in comparison with the other techniques for expanding the coverage area, it also introduces its own set of complements. As an illustration, we beg you to refer to Figure 1 - which is a schematic diagram of an exemplary three-site radiofrequency communications system 10 of simultaneous terrestrial land mobile radio transmission. 10 includes three sim transmitter sites Yes SI, S2 and S3. The transmissions of the SI site cover the coverage area Al and similarly the transmissions of the S2 and S3 sites cover the respective coverage areas A2, A3. A central control point C coupled to each of the SI, S2 and S3 sites through the respective communication links (L1-L3) provides, in real time, essentially identical signals (including digital control channel signals and information associated timer) for transmission through the different sites. Each RF channel in all sites is modulated with ample corrected information of amplitude, phase and time delay. To achieve this, the stable and easy time communication links should be provided between a site of a main control point and all other radio broadcast sites simultaneously by means of a stable basic structure communication system arrangement in phase of superior quality (eg, radio, microwave or fiber optic). In this regard, commercial common wire carriers do not provide the degree of stability required for simultaneous broadcasting; while the dedicated, speech-controlled or voice / data synchronous, user-controlled multiplexer used in conjunction with the distribution paths, basic radio, microwave or fiber optic structure most effectively provide the necessary communication circuits and sterility for simultaneous broadcasting. The exemplary system 10 is preferably a digitally linked simultaneous broadcasting communications system of the type sold by Ericsson-GE Mobile Communications Inc. (EGE) under the name of EDACS factory. This system provides a digital RF control channel and multiple RF work channels. In this digitally linked system, an exemplary mobile radio unit M within one (or more) coverage areas A1-A3 continuously monitors an "outgoing" digital control channel when it is not actually engaged in active communications in a broadcast channel. I work with other units. The mobile M can request communications by transmitting a channel assignment request message in an "input" control channel. Upon receipt of this channel assignment request (and assuming that at least one working channel is available for temporary assignment to the mobile unit M and other units with which the mobile unit M wishes to communicate), the control point C responds causing a control channel assignment message that is transmitted through each S1-S3 site through the output control channel. In the simultaneous broadcasting system 10, this channel assignment message is transmitted simultaneously by each of the transmission sites S1-S3 through the same frequency of the output control channel (such that the mobile unit M and the other mobile units "called" by the channel assignment message will receive the message independently within which of the coverage areas A1-A3 may be placed). The mobile unit M (and other mobile units called) respond to the linked output control channel assignment message received by changing the frequency to an RF working channel and carrying out the communications in the working channel. Once the communications of the working channel are concluded, the mobile unit M (and other so-called mobile units) returns to monitor the output control channel for additional messages directed to them. Referring again to Figure 1, suppose that the mobile unit M is placed within an overlapping area X, where the coverage areas A2 and A3 overlap one another. Within this overlapping area X, the mobile unit M will receive (possibly at approximately equal signal strength levels) the output control channel truncation from site S2 and also the output control channel transmition from site S3. The simultaneous broadcast system 10 is appropriately designed such that these output control channel transmissions from the sites S2 and S3 are essentially at the same RF frequency so that no heterodyne signal or other interference occurs. Similarly, the control point C sends, via links L1-L3, essentially identical output control channel messages for transmission through each of the sites S1-S3.

However, a problem may arise if the output control channels are not synchronized precisely with respect to each other. A transceiver placed within the overlap region X that receives output control channel synchronization signals delayed with respect to each other, by still a small period of time (e.g., more than a half-bit period, or approximately 52 microseconds for the operation of 9,600 baud) could end up losing bits and / or temporarily losing synchronization, and bit and error recovery checking capabilities. The delays due to the limited speed at which the electromagnetic waves propagate must be taken into account in systems that simultaneously transmit the data radially at high data transmission rates (an RF signal goes "only" at approximately 300 meters in one microsecond). It is possible (and usually necessary) to adjust the relative effective radiated power levels of the site transmitters so that distances across the X regions of overlap are kept below a desired maximum distance - and therefore, the difference in the RF propagation delay times across an overlap region due to the different RF path lengths between the site and a receiver within the overlap region, is minimized. Even with this optimization, however, it has been found that (due to the additional differential delay caused by the different lengths of the RF path) a differential stability of the maximum system of + 5 microseconds must be observed to ensure that the transceiver, in one location arbitrary within a typical overlap region X receives the edges of the corresponding digital signal bit within 52 microseconds, one with respect to the other. Fortunately, it is typically possible to minimize the time delay differences within the order of one microsecond through the various known techniques. For example, it is well known in the art to introduce adjustable delay networks (and phase-equalization networks) aligned with some other links Ll-L3 between the sites to compensate for the inherent differential link delay times (see US Pat. No. 4,516,269). granted to Krinock and United States Patents Nos. 4,696,051 and 4,696,052, granted to Breeden, for example). Conventional microwave and optical fiber link channels exhibit amplitude, phase and delay characteristics that are extremely stable over extended periods of time (eg, many months) so that these additional delays, once have adjusted, they guarantee that an input to the signal towards all links L1-L3 between the sites at the same time will reach the other ends of the links almost exactly at the same time. Equal or additional delays can be used to compensate for the different constant delay times introduced by a signal processing equipment at the S1-S3 sites to provide simultaneous co-transmitting of the signals by the different sites. For example, the previously identified Patent Application of Rose and others describes a technique wherein additional frequency, timed information, is provided, each site through one or more inter-site link channels in order to eliminate timing ambiguities. that may result from the use of conventional modems of the multiple-level and multi-level protocol type. In this way, the coherence of the forces of the simultaneous broadcasting system mentioned above at the beginning of the transmission of data in a specific communication path established thereby correcting any ambiguity of multiple bits created by the communication link modem between the sites . Abbreviating, now referring to Figure 2, which generally illustrates a multiple-site Ericsson-GE (EGE) multiple site broadcasting transmission system of the type described in accordance with the aforementioned Rose, et al. patent, a 100"circuit. Resin master (of resynchronization signal) placed at site C of the control point produces reference edges / tones, e.g., at 2400 Hz and 300 Hz, which are sent to each transmission site (S1-S2 ) on a dedicated channel through the inter-site communication links (L1-L2). The digital and speech or voice data aligned with these reference signals are also sent through the communication links (L1-L2) between the control point C and the transmission sites (S1-S2). The lowest tone (300 Hz) is used as a reference (for reading timing of a broadcast data buffer at the transmition sites) that the highest tone (2400 Hz) is used as a reference for the clock frequency of data. Each transmission site (S1-S2) in the simulcasting system includes a "Universal" resynchronization circuit (ie, common hardware) to retrieve the reference edges of the tones. Through the operation of a periodic "resine" operation, the universal resine circuit at each site of the simultaneous broadcasting system, realigns the received broadcast data through the links between the sites towards these reference edges. Consequently, as mentioned above, it is required that the signal paths for these reference tones (which are conventionally provided through the links between the sites) are of high quality and very stable in phase, since any variation or noise in these signals will have a detrimental effect on the operation of the total simultaneous broadcasting system. Therefore, it is known how to resynchronize the control channel at each transmitter site periodically on a routine basis in order to correct any of the control channel timing errors that may arise in the simultaneous broadcast system 10. In addition, the previously identified US Patent Application Serial Number 07 / 824,123 to Brown et al., Filed on January 22, 1992, discloses additional techniques (which have been in public use for more than a year and therefore represent the prior art for the present request) in order to periodically "disconnect" a site modem in order to ensure that the modem uses a common distributed clock signal; and to "re-train" a communication link and the associated site modems for a simultaneous broadcast system work channel if a "test call" of the work channel carried out routinely fails (as described in U.S. Patent No. 4,903,321 issued to Hall and others). With respect to the EGE simultaneous broadcasting systems mentioned above, the applicant has disclosed in the present specification an improved method and apparatus for generating resynchronization tones at each transmitting site that increases the reliability of the synchronized timing through a Simultaneous broadcasting system and greatly simplifies the procedure for the alignment of the simultaneous broadcasting system. More specifically, an improvement in the operation of the system is achieved by providing a global positioning satellite receiver (GPS) at each transmitter site to serve as the source for generating the precise, stable frequency reference tones necessary for periodic operations of " Resine. " The GPS system traditionally used for navigation purposes is a series of satellites synchronized in time and continuously transmitting, inter alia, time, date and placement information. Although the sites of the cellular radiotelephone system using GPS to provide absolute timing are known, these systems tend to inherent problems that make these systems expensive and unreliable (see, for example, US Patent Number 5,245,634 issued to Averbuch) . In accordance with the present invention, an improved multi-site multi-site RF broadcasting system is achieved, using the broadcast signals of the GPS system together with a specific resynchronization circuit arrangement at each simultaneous broadcast site overcoming many of the inconveniences. of the previous synchronized GPS systems. In accordance with the present invention, the resynchronization reference signals are not sent to transmission sites with the broadcast signals through the site interconnection links (L1-L2, etc.). Instead, each simultaneous broadcast site includes a "resine" circuit of the "universal" (generic) EGE simulcasting system and the resynchronization of the simultaneous broadcast data is carried out periodically on a routine basis by each site of the broadcast. system separately and independently. In a preferred exemplary embodiment, the stable data clock reference requires 9, 600bps and the lowest frequency signal (eg, 300Hz, as described above) are derived separately at each site of the simultaneous broadcasting system of a global positioning satellite broadcast (GPS) transmission using a GPS receiver at each site. The checkpoint site (C) includes a universal "resine" EGE circuit and is no longer used as a "master" circuit. The "resine" circuit in each site uses the tones from the reference signal derived from GPS to align the RF broadcasting of the simultaneous broadcast data. Consequently, the dedicated stabilized channels in the interconnection links of the site are no longer needed to disturb the tones of the "resine" reference signal. In addition, because the "resine" EGE operation will force alignment with the timing of the correct concurrent broadcast system, any variation in the interconnect link latency of the site is automatically corrected when a "resine" operation is performed. (as long as the latency variation is within the signal timing window) without any measurement or link latency correction. Conventional commercial simultaneous broadcast systems that are not of the EGE type, if similarly equipped with the GPS receivers, would require an arithmetic calculation of latency change and / or storage of the link timing parameters. further, employing a GPS receiver in combination with a universal EMS "resine" circuit in an arrangement for generating "resine" reference sockets for the resynchronization circuit and autonomously aligning the data broadcasting at each site in accordance with this invention, further enhances the simultaneous broadcast operations by reducing the timing vibration and eliminating the need to align the checks on the polarity of the reference tone. Because the fine tuning of a specific multiple site simultaneous broadcasting system arrangement requires specific adjustments to the broadcast timing in one or more sites outside the equal "nominal" timing, you must provide a method to produce these timing off-centerings . In accordance with a further aspect that is provided by means of the present invention, the GPS receiver uses a delay unit which provides adjustable signal delays of ± 125 microseconds in incremental steps of 0.5 microseconds and which is accessible through an RS port. -232. Correspondingly, a further advantage is achieved by the present invention since the fine tuning timing settings of the simultaneous broadcasting system can be made remotely through an RS-232 link.

BRIEF DESCRIPTION OF THE DRAWINGS These and other features and advantages of the present invention will be more fully understood by reference to the following detailed description of the currently preferred exemplary embodiments together with the Figures in which the reference numbers refer to elements same: Figure 1 is a general schematic illustration of a simplified exemplary multiple site RF communication simulcasting system; Figure 2 is a general schematic functional diagram of the central control point C and the transceiver sites SI and S2 distant from a multiple site Ericsson-GE RF multicast communication system of a type wherein the operation of the present invention may be particularly appropriate; Figure 3 is a general schematic functional diagram of an exemplary arrangement of a modified multiple site RF multicast communication system using GPS receivers to improve the generation of the resynchronization reference signal at each site.

DETAILED DESCRIPTION OF THE DRAWINGS In the following description, specific details such as specific circuits, circuit components, interfaces, techniques etc. are disclosed for the purpose of explanation and not limitation. in order to provide a complete understanding of the present invention. However, it will be apparent to a person skilled in the art that the present invention can be implemented in other embodiments that deviate from these specific details. In other cases, detailed descriptions of well-known programming methods, devices and circuits are omitted so as not to complicate the description of the present invention in unnecessary detail. The basic architecture of a Ericsson-GE simulcasting system as described above is shown in Figures 1 and 2 - that is, it includes a central control point C and multiple Sl ... Sn transmitter sites. Even though only two transmitting (distant) S1-S2 sites are shown in Figures 2 and 3 only, it will be appreciated by a person skilled in the art that numerous distant sites participating in the simultaneous radio transmission also remain in communication with the control point. C through links Ll-Ln microwave communication path, fiber optic, cable and landline. In addition, the present invention is not limited to exclusive use with a microwave or landline link, but can be used with any other type of appropriate communication link, such as a radio wave. In the RF transmission system of simultaneous radiofrequency multiple site radio transmission, the data provided through the communication links between the sites (Ll, L2, etc.) from the control point C to the RF transmitting sites ( Sl, S2, etc.) exhibits random time delay because the multiple phase link modems (MC, MI, M2, etc.) at each site recover the clock signals of an arbitrary phase of the multiple phases. The data stream outputs of the modems are temporarily stored in the sites in MI, M2, etc., buffers associated with the modem in each site. The timing information that is provided at each site from the control point C through the link channels initially rates the timing of the buffer output at each site to eliminate transmission timing ambiguities. On a continuous basis, the "resine" circuit in the sites periodically resynchronizes the timing of the buffer output in accordance with a pair of reference frequency tones that are continuously provided to each site through the link channels dedicated from control point C, as discussed above in the foregoing. Referring now to Figure 3, an exemplary embodiment of a modified multisite RF communication broadcasting system in accordance with the present invention is discussed. The GPS receivers 301, 301a and 301b, at all sites (including the control point C) provide a reference signal acquired from a common GPS timing signal broadcasting through the satellite 300. The circuits 302, 302a, 302b, tone generators at each site use the received GPS timing reference signal to generate a high frequency data clock reference tone of 9,600 bps and a low frequency data tone (timing) that are used by the circuits 303, 303a, 303b of universal "resine", to carry out the periodic operations of "resine". In accordance with the present invention, a much lower signal frequency may be used, for example, than 300 Hz as long as the selected frequency is an integral submultiple of the timing of the data stream frame (i.e. of the data box divided by the frequency period) and a submultiple of 9,600 (eg using 100 Hz a period of 10 milliseconds is provided; 60 Hz provides a period of 16.6 milliseconds; etc.). The frequency of preference is selected based on the expected system link latency variations. The resynchronization reference tones are not sent to the transmission sites through the communication links between the sites from a designated control point site as in the exemplary EGE simultaneous broadcast systems discussed above. Consequently, additional stable channels are not required in phase and compensated in delay for the signals of "resine", instead of this, a "resine" operation is carried out periodically on a continuous basis by the circuits 303, 303a, 303b of universal "resins" in each site of the simultaneous broadcasting system using the "resine" reference tones derived from the GPS signal received by the tone generator circuits 302, 302a, 302b. The re-timed (re-aligned) data in this manner is provided on a continuous basis to the transmitters 304a, 304b of the channel at each site for simultaneous RF transmission. In addition, because a "resine" operation forces the alignment of the data stream to the timing of the correct simultaneous broadcast system, any variation of interconnect link latency between the sites (within the signal timing window) ) will be corrected automatically when the resynchronization operation is carried out. In addition, this modified arrangement for providing resynchronization reduces the vibration of the timing and eliminates the need to align the checks on the plurality of the reference tone. As also illustrated in Figure 3, receivers 301, 301a, 301b, GPS include a delay unit which provides adjustable signal delays of +125 microseconds in incremental steps of 0.5 microseconds and which is controllable through an RS-port. 232 Accordingly, a further advantage is achieved by the present invention since the fine tuning timing settings of the simultaneous broadcasting system can be made remotely through an RS-232 link. Even though the invention has been described in relation to what is currently considered to be the most practical and preferred embodiment, it should be understood that the invention is not limited to the modality disclosed, but rather is intended to protect the various modifications and equivalent provisions included within the spirit and scope of the appended claims.

Claims (8)

1. R E I V I N D I C A C I O N E S; 1.
2. In a radiofrequency (RF) communication system of simultaneous radial transmission and the type having a central site that provides a stream of high-speed data signals, comprising timed data frames to the multiple RF transmitting sites, and each one of the transmitter sites includes a multi-phase modem and a data buffer medium for receiving, storing the high-speed data signal stream, the data signals received at each transmitter site have time ambiguities with respect to the data signals received at another transmitting site, each of the transmitting sites further includes means for periodically resynchronizing and consistently transmitting radially coherently of the high-speed data signal streams through a common RF channel, comprising: a receiver of satellite reference timing broadcasting signals global ion (GPS); a "resine" tone generator, the tone generator provides a pair of reference frequency tones synchronized to a broadcast GPS timing reference signal received by the GPS receiver; and a universal resynchronization circuit that responds to the pair of reference tones, the universal resynchronization circuit synchronizes a reading of the buffer medium of the stream of high-speed data signals received and stored to effect a simultaneous transmission through the sites of Multiple RF The simultaneous radio transmission communication system according to claim 1, wherein the resynchronization tone generator produces a 9,600 Hz data clock reference signal and a low frequency data tone.
3. 3. The communication system "of simultaneous radial transmission according to claim 2, wherein the low frequency data tone is an integral submultiple of the timing of the data stream board of the simultaneous radial transmission system and a submultiple of 9,600.
4. The simultaneous radio transmission communication system according to claim 2, wherein the low frequency data tone is 300 Hz.
5. 5. In a radio-frequency (RF) communication system of simultaneous radial transmission of the type having a central site that provides a stream of high-speed data signals to the multiple RF transmitting sites, the data signals received at each site transmitter have ambiguities of time with respect to the data signals received at another transmitting site, an improved means at each of the transmitting sites to synchronize and transmit coherently radially simultaneously through a common RF channel, the information of the high-speed data signal streams, comprising: a receiving means for receiving and extracting a timing reference signal from the broadcast transmission of the GPS system; a resynchronization tone generating means for generating a pair of resynchronization reference frequency tones synchronized to the GPS signal; a buffer means for receiving and storing the stream of high-speed data signals; and a universal resynchronization circuit means responsive to the pair of reference tones to periodically resynchronize a reading of the high-speed data signal stream on a continuous basis, with at least one of the resynchronization reference frequency tones. .
6. 6. In a simultaneous broadcast radio frequency communication system having multiple remotely-separated RF transmitters that transmit essentially the same radio signal at essentially the same radio frequency, each of the RF transmitters has an associated GPS receiver, a method to periodically resynchronize the radio signals transmitted from each of the RF transmitters, including the steps of: (a) temporarily storing the data of the radio signal to be transmitted in a buffer in each of the RF transmitters; (b) generating a pair of resynchronization reference tones synchronized to the GPS signal; (c) periodically resynchronizing, on a continuous basis in each of the multiple transmitters, the reading of the stored radio signal data to be transmitted out of the buffer for periods of time and at a rate that responds to the tone pair of reference.
7. 7. A simultaneous radiofrequency (RF) radio transmission system of the type that includes a control point connected by data links to multiple remote radio frequency transmitters, a clock signal synchronized to a satellite signal broadcast of global positioning (GPS) received by being available at the control point, an improved method to provide high-speed digital data transmissions essentially simultaneously from multiple transmitters, the improved method includes the steps of: distributing the high-speed digital data from the control point to the multiple transmitters through the data links during periods of time that respond to the clock signal available at the control point, the distribution of the high-speed data includes the steps of receiving and storing the data high speed in a buffer in each of the multiple transmitters; receive a timing reference signal from the GPS broadcast in each of the transmitters; generate timing / frequency signals in each of the transmitters synchronized to the received GPS reference signal; generating an additional clock signal in each of the transmitters in response to the generated timing / frequency signals; synchronizing, in each of the multiple transmitters, the reading of the high-speed digital data stored outside the buffer for periods of time and at a rate that responds to the timing / frequency signals and the additional clock signal; and transmit the read synchronized data through the RF channels. A method according to claim 7, wherein the step of synchronizing includes the step of periodically resynchronizing, on a continuous basis, the reading of the high-speed digital data stored outside the buffer to a rate responsive to the timing / frequency signals. SUMMARY OF THE INVENTION In a radio frequency multiple site transmission system R.F. of simultaneous radial transmission, the data provided through inter-site communications links (L1, L2, etc.) from a control point to the transmitting sites of R.F. it exhibits a skewed random time delay because the multi-phase modems retrieve the clock signals of an arbitrary phase of the multiple phases. The output data streams of the modems are temporarily stored in the intermediate memory sites for temporary alignment for transmission of R.F. simultaneous. The buffers in each site are periodically resynchronized on a continuous basis by a universal "resine" circuit to maintain the optimal functioning of the simultaneous broadcasting system. A data clock reference of 9600 bps and a low frequency data signal (timing) to carry out a periodic "resine" operation are derived separately from a common satellite reference signal acquired using a GPS receiver (global positioning satellite) at each site of the simultaneous broadcasting system. A resynchronization operation on a continuous basis is performed periodically separately by each simulcasting system and the distributed multisite broadcasting data stream is aligned using the resynchronization reference tone derived from the received GPS signal.