CA1306502C - Simulcast broadcasting system and method - Google Patents
Simulcast broadcasting system and methodInfo
- Publication number
- CA1306502C CA1306502C CA000608982A CA608982A CA1306502C CA 1306502 C CA1306502 C CA 1306502C CA 000608982 A CA000608982 A CA 000608982A CA 608982 A CA608982 A CA 608982A CA 1306502 C CA1306502 C CA 1306502C
- Authority
- CA
- Canada
- Prior art keywords
- signal
- remote sites
- broadcast
- signals
- simulcast
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/65—Arrangements characterised by transmission systems for broadcast
- H04H20/67—Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
- H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
- H04B7/2625—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile using common wave
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Radio Relay Systems (AREA)
- Mobile Radio Communication Systems (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
- Diaphragms For Electromechanical Transducers (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
IMPROVED SIMULCAST BROADCASTING SYSTEM AND METHOD
Abstract of the Disclosure A simulcast broadcast system wherein two signals (103 and 106) intended for simultaneous broadcast are transmitted from a source site (100) to remote sites (200) discrete from one another. At the remote sites, the two signals are separately processed, including the introduction of appropriate delay (305 and 312), prior to combining them for broadcast in conjunction with other remote sites. One or more monitoring sites (400) can also be provided to monitor reception coherence within the system and to provide operating measurement information to allow automatic control of various simulcast system parameters, including delay.
Abstract of the Disclosure A simulcast broadcast system wherein two signals (103 and 106) intended for simultaneous broadcast are transmitted from a source site (100) to remote sites (200) discrete from one another. At the remote sites, the two signals are separately processed, including the introduction of appropriate delay (305 and 312), prior to combining them for broadcast in conjunction with other remote sites. One or more monitoring sites (400) can also be provided to monitor reception coherence within the system and to provide operating measurement information to allow automatic control of various simulcast system parameters, including delay.
Description
130~
SIMULCAST BROADCASTING SYSTEM AND METHOD
Technical Field This invention relates generally to simulcast radio cornmunications systems.
Background Art Simulcast radio comrnunications systems are typically employed to provide wide area one-way or two-way radio communications services. In such a system, a source site typically originates (or forwards from another originating site) a signal to be generally broadcast. This signal is routed from the source site to a plurality of remote sites. Each remote site then simultaneously broadcasts the signal with other remote sites to facilitate reception of the signal by receivers within the area covered by the system.
In this way, a receiver outside the operating range of one remote site may stillbe within the range of one or more other remote sites, thereby reasonably ensuring that the receiver can receive the signal.
One particularly difficult problem with such simulcast systems involves coordinating the various \
. " .f ..
l;~a6s~z remote sites to ensure that the signals are in ~act substantially simultaneously broadcast by ea~h. A
failure to accompllsh this will result in instances of unacceptable reception coherence as potentially caused by phas~ orfsets, deviation, distortion and the like.
Another problem arises when more than two signals must be transmitted simultaneously; for example, a voice signal and a data signal. Prior art methods of processing such combined signals in a simulcast environment have not always been ade~uately conducive to supporting necessary levels of reception coherence.
Finally, even when initially properly adjusted for proper reception coherence, the operating per~ormance of a given simulcast system may vary in responce to a number of changing operating and environmental factors.
No prior art systems provids for a means of allowing a simulcast system to respond in any convenient or efficaclous manner to such circumstances.
A need exists for a simulcast system that provides for the substantially simultaneous broadcast of a signal from a plurality of remote sites, particularly where the signal to be broadcast itself $ncludes at least two signals. A need further exists for a system that can adapt one or mor~ of its operating parameters to continually provide transmissions of acceptable reception cohsrencQ even when other operating factors or envlronmental conditlons change.
Summarv Or the Invention These needs and others are substantially met through provision of the improved simulcast broadcasting system disclosed herein. The system includes generally a source site for providing an original signal to be broadcast, and a plurality o~ remote sites for subs~antially simultaneously broadcasting the original siynal from the source site.
~ 3 13~6S~2 ~M-00467H
In one embodiment, the source site provides both a first and a second signal (~uch as voice and data).
The source site provides thesle ~wo signals to the remote sites discrete from one ano~her. Only a~ter reception and appropriate processing at the remote site will the two signals be combined to facilitate their broadcast.
In one embodiment, the appropriate processing provided to the first and second signals a~ the remote sites includes introduction of an appropriate time delay to ensure that all of the remote sites broadcast substantially the same signal with substantially the same phase relationship.
In another embodiment, a monitoring device can be provided to monitor broadcast signals from the remote sites, and determine whether the broadcast signals exhibit an acceptable reception coherence. One or more broadcast system parameters can then be automatically varied in response to this determinatlon as appropriate to improve rsception coherence.
Brief De~cription of the Drawinqs Fig. 1 comprise~ a block diagram depiction of source site structure;
Flg. 2 comprises a block diagram depiction of remote site strUcture:
Fig. 3 comprises a block diagram depiction of the remote delay module of the remote site; and Fig. 4 comprises a block diagram depiction of a monitoring sitQ.
~est Mode for ~arry-ing out the Invention The invention includes generally a source si~e unit lSSU) (100) ~Fig. 1) and a remote site unit (RSU) (200) (Fig. 2).
13~ 0Z
Referring to Fig. 1, the SSU (100) includes generally a microwave radio (101~ that raceives both audio and data input. The microwave radio (101) functions to transmit the two incoming signals in a known multiplexed manner to the RSUs (200) ag described below in more detail.
The SSU audio p~th (102) lncludes an audio source input (103) (which may be on ~ite or o~, as may be appropriate to the application or function) that pas~es through a transmission block (104) conrigured in known manner as a double sideband/reduced carrier, the output o~ whlch transmitter (104) couples to a transmitter input port of the microwave radio (101). In certain applications, as in trunked communications, this input (103) could alternatively receive high speed data, such as control channel signalling.
Ths data path (105) includes a data source (106) (which provides, for example, low cpeed data intended to be ultimately coupled subaudibly with the audio information). The data source (106) pa~ses through an FSK modulator (107) to a single sideband configured transmitter (108). The latter transmitter (108) sums to a transmit port of the microwave radio (101).
For pUrpO8Q5 of explanation, the audio signal can be a ~irst ~ignal, and the data signal can be a second signal, with the ultimate intent being to provide a signal to a subscriber unit, such as a mobile, portable or ~ixed receiver, in a combined format. Upon reception, the radio will render ~he voice information audible, and 30 will subaudibly process and act accordingly upon the data information or in~tructions. It should be noted that in this system, contrary to prior art technique, the rirs~
and sQcond ~ignals are not combined at the SSU (100).
Instead, they are transmitted separately and discrete from one another, in a multiplexed manner, to the ~SUs (20~).
_ 5 13Q65~ CM-00467H
Referring now to Fig. 2, an example RSU (200) will be described. The RSU (200) includes a repeater structure comprised of two microwave radios (201 and 202). Signals received by the first microwave radio (201) ar~ sub6equently repeated and transmitted by the se~ond microwave radio (202), ~or instance to another RSU. Similarly, signal~ received fro~ down stream RSUs can be received by the second microwave radio (202) and transmittQd to the ssu via the flrst microwave radio 10 (201). Again, these radios (201 and 202) function in a known manner to recoive and transmlt multiplexed signals, including the first and second signals provided by the SSU (100).
The RSU (200) also includes a combiner (203) as woll understood in the art. The combiner provides a high frequency received information line (204) and a high frequency transmit in~ormation line (205). A single sideband conrigured receiver (20~) couples to the receive line (204) and ~unctions to receive the data information as transmitted by the SSU (100). A double ~ideband/reduced carrier configurated receiver (207) also couples to the receive line (204) and functions to receive the audio information a~ separately transmitted by the SSU (100).
The output of both receivers (206 and 207) is provided to a remote delay modul~ (RDM) (203), the con~iguration and operation o~ which will be described in more detail below. The output (209) of the remote delay module includes recovered audio infor~ation and recovered data information, appropriately processed, delayed, and combined. This combined signal can then be provided to appropriate transmitter equipment to allow a general broadcast of the informat~on in a known manner.
The RSU (200) al~o includes a single sideband configured transceiver (210) that couples to both high frequency lines o~ the combiner (203) and communicates with a processor unit (211) that provides appropriate 13~65(~
control instructi~n~ to the RDM (208) as also described in more detail below.
Referring now to Fig. 3, the RDM (208) includes a data path (301) and an audio path (302). The data path (301) couples to the output of the single sideband receiver (206) through a 600 ohm input unit (303), ~ollowing which the signal i~ appropriately clipped and squared (304~ in a known manner. The data signal is then passed through an appropriate delay unit (305). The delay unit (305) introduces a time delay in any appropriate known manner to accomplish a prede~ermined delay o~ propagation of the data signal to the transmitter of the RSU (200). (The purpose of this delay i8 to ensure that all RSUs (200) transmit a given ~ource signal as provided by the SSu (lOo) at substantially the same time. Therefore, the delay at any particular RSU
(200) will llkely be unique to that RSU.) The delayed data signal then pas~es through an appropriate FSK
deaoder (306) and subaudible data splatter filter (307) to a digital attenuator unit (308). Following appropriate att~nuation as required to provide necessary equalization, the data signal is provided to a summing unit (309), the operation of which will be disclosed in more detail below.
The audio path (302) connects to the output of the double sideband/reduced carrier receiver (207) through an appropriate 600 ohm input (310). The audio signal is then passed through an appropriate anti-alias filter (311) to a delay unit (312), the function and purpose of which is the same as that described above for the data path delay unit (305).
Following introduction of the appropriate delay, th~ audio signal passes through an appropriate splatter filter (313) and digital attenuator (314) to provide th~
necessary equalization, following which the signal passes through a highpass filter (315) to the summing unit (309).
~306X~z The summing unit (309) functions to sum the delayed and properly processed data s;gnals with the delayed and properly processed audio signals to thereby provide a distinct composite signal. This dist;nct composite signal thenpasses through an appropriate 600 ohm output unit (316) for subsequent processing (209) as referenced above. (In a trunked system, as noted earlier theaudio path (302) may receive high speed data instead of voice information. To accommodate such an embodiment, the inputs to the summing unit (309) can be controlled by a number of logic gates (317, 318, and 319) that res~ond to an appropriate control signal (320). So configured, the summing unit (309) will receive either both high pass filtered audio information and low speed data, or high speed data only that has not been high pass filtered.) It should be noted that the signal processing, such as equalization and introduction of delay, occur at the RSU (200) as versus the SSU (lO0). Also,it should be noted that, at the RSU (200), the first and second signals are individually and separately provided with the appropriate delay and other signalcompensation factors prior to their combination.
In Fig. 3, it can also be seen that the delay units (305 and 312) and the digital attenuators (308 and 314) can be controlled by the processor (211) referenced above. The processor (211) in turn can receive data information and/or instructions from the SSU (lO0) through the microwave radio link. As a result, instructions regarding the appropriate delay and attenuation can be formulated at the SSU (lOO)and transmitted to the various RSUs (~00), and implemented without human intervention.
With reference to Fig. 4, a monitoring site (400) in accordance with the invention can be seen as depicted generally by the numeral 400. A typical monitoring site includes a signal processing unit (401) that could include, for example, a number of directional antennas , . \ ~ ) ~
1306~(~2 (4023. Each ant~nna ~402~ could be dixected to a particular RS~ (200). The signal processing unit (401) utilizes that information to develop information regarding reception coherence ~or signals broadcast by the RSUs (2003. A processor (403) can be provided that takes the reception coherence information developed by the signal processing unit (401) and compares it against an appropriate threshold or other criteria. Information regarding the comparisons developed by the processor (403) can be transmitted via an appropriate radio (404) or other link to the SSU (lO0) or other control location.
Based upon information developed by the monitoring Sit2 (400) regarding reception coherence, the delay and/or attenuation parameters for a given RSU (200) can be selectively varied to accommodate changing operating or environmental conditions.
SIMULCAST BROADCASTING SYSTEM AND METHOD
Technical Field This invention relates generally to simulcast radio cornmunications systems.
Background Art Simulcast radio comrnunications systems are typically employed to provide wide area one-way or two-way radio communications services. In such a system, a source site typically originates (or forwards from another originating site) a signal to be generally broadcast. This signal is routed from the source site to a plurality of remote sites. Each remote site then simultaneously broadcasts the signal with other remote sites to facilitate reception of the signal by receivers within the area covered by the system.
In this way, a receiver outside the operating range of one remote site may stillbe within the range of one or more other remote sites, thereby reasonably ensuring that the receiver can receive the signal.
One particularly difficult problem with such simulcast systems involves coordinating the various \
. " .f ..
l;~a6s~z remote sites to ensure that the signals are in ~act substantially simultaneously broadcast by ea~h. A
failure to accompllsh this will result in instances of unacceptable reception coherence as potentially caused by phas~ orfsets, deviation, distortion and the like.
Another problem arises when more than two signals must be transmitted simultaneously; for example, a voice signal and a data signal. Prior art methods of processing such combined signals in a simulcast environment have not always been ade~uately conducive to supporting necessary levels of reception coherence.
Finally, even when initially properly adjusted for proper reception coherence, the operating per~ormance of a given simulcast system may vary in responce to a number of changing operating and environmental factors.
No prior art systems provids for a means of allowing a simulcast system to respond in any convenient or efficaclous manner to such circumstances.
A need exists for a simulcast system that provides for the substantially simultaneous broadcast of a signal from a plurality of remote sites, particularly where the signal to be broadcast itself $ncludes at least two signals. A need further exists for a system that can adapt one or mor~ of its operating parameters to continually provide transmissions of acceptable reception cohsrencQ even when other operating factors or envlronmental conditlons change.
Summarv Or the Invention These needs and others are substantially met through provision of the improved simulcast broadcasting system disclosed herein. The system includes generally a source site for providing an original signal to be broadcast, and a plurality o~ remote sites for subs~antially simultaneously broadcasting the original siynal from the source site.
~ 3 13~6S~2 ~M-00467H
In one embodiment, the source site provides both a first and a second signal (~uch as voice and data).
The source site provides thesle ~wo signals to the remote sites discrete from one ano~her. Only a~ter reception and appropriate processing at the remote site will the two signals be combined to facilitate their broadcast.
In one embodiment, the appropriate processing provided to the first and second signals a~ the remote sites includes introduction of an appropriate time delay to ensure that all of the remote sites broadcast substantially the same signal with substantially the same phase relationship.
In another embodiment, a monitoring device can be provided to monitor broadcast signals from the remote sites, and determine whether the broadcast signals exhibit an acceptable reception coherence. One or more broadcast system parameters can then be automatically varied in response to this determinatlon as appropriate to improve rsception coherence.
Brief De~cription of the Drawinqs Fig. 1 comprise~ a block diagram depiction of source site structure;
Flg. 2 comprises a block diagram depiction of remote site strUcture:
Fig. 3 comprises a block diagram depiction of the remote delay module of the remote site; and Fig. 4 comprises a block diagram depiction of a monitoring sitQ.
~est Mode for ~arry-ing out the Invention The invention includes generally a source si~e unit lSSU) (100) ~Fig. 1) and a remote site unit (RSU) (200) (Fig. 2).
13~ 0Z
Referring to Fig. 1, the SSU (100) includes generally a microwave radio (101~ that raceives both audio and data input. The microwave radio (101) functions to transmit the two incoming signals in a known multiplexed manner to the RSUs (200) ag described below in more detail.
The SSU audio p~th (102) lncludes an audio source input (103) (which may be on ~ite or o~, as may be appropriate to the application or function) that pas~es through a transmission block (104) conrigured in known manner as a double sideband/reduced carrier, the output o~ whlch transmitter (104) couples to a transmitter input port of the microwave radio (101). In certain applications, as in trunked communications, this input (103) could alternatively receive high speed data, such as control channel signalling.
Ths data path (105) includes a data source (106) (which provides, for example, low cpeed data intended to be ultimately coupled subaudibly with the audio information). The data source (106) pa~ses through an FSK modulator (107) to a single sideband configured transmitter (108). The latter transmitter (108) sums to a transmit port of the microwave radio (101).
For pUrpO8Q5 of explanation, the audio signal can be a ~irst ~ignal, and the data signal can be a second signal, with the ultimate intent being to provide a signal to a subscriber unit, such as a mobile, portable or ~ixed receiver, in a combined format. Upon reception, the radio will render ~he voice information audible, and 30 will subaudibly process and act accordingly upon the data information or in~tructions. It should be noted that in this system, contrary to prior art technique, the rirs~
and sQcond ~ignals are not combined at the SSU (100).
Instead, they are transmitted separately and discrete from one another, in a multiplexed manner, to the ~SUs (20~).
_ 5 13Q65~ CM-00467H
Referring now to Fig. 2, an example RSU (200) will be described. The RSU (200) includes a repeater structure comprised of two microwave radios (201 and 202). Signals received by the first microwave radio (201) ar~ sub6equently repeated and transmitted by the se~ond microwave radio (202), ~or instance to another RSU. Similarly, signal~ received fro~ down stream RSUs can be received by the second microwave radio (202) and transmittQd to the ssu via the flrst microwave radio 10 (201). Again, these radios (201 and 202) function in a known manner to recoive and transmlt multiplexed signals, including the first and second signals provided by the SSU (100).
The RSU (200) also includes a combiner (203) as woll understood in the art. The combiner provides a high frequency received information line (204) and a high frequency transmit in~ormation line (205). A single sideband conrigured receiver (20~) couples to the receive line (204) and ~unctions to receive the data information as transmitted by the SSU (100). A double ~ideband/reduced carrier configurated receiver (207) also couples to the receive line (204) and functions to receive the audio information a~ separately transmitted by the SSU (100).
The output of both receivers (206 and 207) is provided to a remote delay modul~ (RDM) (203), the con~iguration and operation o~ which will be described in more detail below. The output (209) of the remote delay module includes recovered audio infor~ation and recovered data information, appropriately processed, delayed, and combined. This combined signal can then be provided to appropriate transmitter equipment to allow a general broadcast of the informat~on in a known manner.
The RSU (200) al~o includes a single sideband configured transceiver (210) that couples to both high frequency lines o~ the combiner (203) and communicates with a processor unit (211) that provides appropriate 13~65(~
control instructi~n~ to the RDM (208) as also described in more detail below.
Referring now to Fig. 3, the RDM (208) includes a data path (301) and an audio path (302). The data path (301) couples to the output of the single sideband receiver (206) through a 600 ohm input unit (303), ~ollowing which the signal i~ appropriately clipped and squared (304~ in a known manner. The data signal is then passed through an appropriate delay unit (305). The delay unit (305) introduces a time delay in any appropriate known manner to accomplish a prede~ermined delay o~ propagation of the data signal to the transmitter of the RSU (200). (The purpose of this delay i8 to ensure that all RSUs (200) transmit a given ~ource signal as provided by the SSu (lOo) at substantially the same time. Therefore, the delay at any particular RSU
(200) will llkely be unique to that RSU.) The delayed data signal then pas~es through an appropriate FSK
deaoder (306) and subaudible data splatter filter (307) to a digital attenuator unit (308). Following appropriate att~nuation as required to provide necessary equalization, the data signal is provided to a summing unit (309), the operation of which will be disclosed in more detail below.
The audio path (302) connects to the output of the double sideband/reduced carrier receiver (207) through an appropriate 600 ohm input (310). The audio signal is then passed through an appropriate anti-alias filter (311) to a delay unit (312), the function and purpose of which is the same as that described above for the data path delay unit (305).
Following introduction of the appropriate delay, th~ audio signal passes through an appropriate splatter filter (313) and digital attenuator (314) to provide th~
necessary equalization, following which the signal passes through a highpass filter (315) to the summing unit (309).
~306X~z The summing unit (309) functions to sum the delayed and properly processed data s;gnals with the delayed and properly processed audio signals to thereby provide a distinct composite signal. This dist;nct composite signal thenpasses through an appropriate 600 ohm output unit (316) for subsequent processing (209) as referenced above. (In a trunked system, as noted earlier theaudio path (302) may receive high speed data instead of voice information. To accommodate such an embodiment, the inputs to the summing unit (309) can be controlled by a number of logic gates (317, 318, and 319) that res~ond to an appropriate control signal (320). So configured, the summing unit (309) will receive either both high pass filtered audio information and low speed data, or high speed data only that has not been high pass filtered.) It should be noted that the signal processing, such as equalization and introduction of delay, occur at the RSU (200) as versus the SSU (lO0). Also,it should be noted that, at the RSU (200), the first and second signals are individually and separately provided with the appropriate delay and other signalcompensation factors prior to their combination.
In Fig. 3, it can also be seen that the delay units (305 and 312) and the digital attenuators (308 and 314) can be controlled by the processor (211) referenced above. The processor (211) in turn can receive data information and/or instructions from the SSU (lO0) through the microwave radio link. As a result, instructions regarding the appropriate delay and attenuation can be formulated at the SSU (lOO)and transmitted to the various RSUs (~00), and implemented without human intervention.
With reference to Fig. 4, a monitoring site (400) in accordance with the invention can be seen as depicted generally by the numeral 400. A typical monitoring site includes a signal processing unit (401) that could include, for example, a number of directional antennas , . \ ~ ) ~
1306~(~2 (4023. Each ant~nna ~402~ could be dixected to a particular RS~ (200). The signal processing unit (401) utilizes that information to develop information regarding reception coherence ~or signals broadcast by the RSUs (2003. A processor (403) can be provided that takes the reception coherence information developed by the signal processing unit (401) and compares it against an appropriate threshold or other criteria. Information regarding the comparisons developed by the processor (403) can be transmitted via an appropriate radio (404) or other link to the SSU (lO0) or other control location.
Based upon information developed by the monitoring Sit2 (400) regarding reception coherence, the delay and/or attenuation parameters for a given RSU (200) can be selectively varied to accommodate changing operating or environmental conditions.
Claims (2)
1. A method of simulcasting a distinct broadcast signal from at least two remote sites, said broadcast signal comprising at least a combined first signal and second signal, the method comprising the steps of:
a) transmitting from a source site said first signal to said at least two remote sites;
b) separately transmitting from a source site said second signal to said at least two remote sites;
c) at said at least two remote sites, delaying said first and second signals by a predetermined amount to provide delayed first and second signals, which predetermined amount may be different for each of said at least two remote sites;
d) combining said delayed first and second signals to provide a distinct composite signal;
e) broadcasting said distinct composite signal substantially simultaneously with other of said at least two remote sites to provide said distinct broadcast signal.
a) transmitting from a source site said first signal to said at least two remote sites;
b) separately transmitting from a source site said second signal to said at least two remote sites;
c) at said at least two remote sites, delaying said first and second signals by a predetermined amount to provide delayed first and second signals, which predetermined amount may be different for each of said at least two remote sites;
d) combining said delayed first and second signals to provide a distinct composite signal;
e) broadcasting said distinct composite signal substantially simultaneously with other of said at least two remote sites to provide said distinct broadcast signal.
2. The method of claim 1 and further including are steps of:
f) monitoring, at least from time to time, said broadcast signal as broadcast by at least some of said at least two remote sites;
g) determining whether said broadcast signal as monitored has acceptable reception coherence;
h) automatically varying at least one of said first signal, said second signal, said composite signal, and said broadcast signal as required to improve said reception coherence.
f) monitoring, at least from time to time, said broadcast signal as broadcast by at least some of said at least two remote sites;
g) determining whether said broadcast signal as monitored has acceptable reception coherence;
h) automatically varying at least one of said first signal, said second signal, said composite signal, and said broadcast signal as required to improve said reception coherence.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US26152888A | 1988-10-21 | 1988-10-21 | |
| US261,528 | 1988-10-21 |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000616300A Division CA1316985C (en) | 1988-10-21 | 1992-01-28 | Simulcast broadcasting system and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1306502C true CA1306502C (en) | 1992-08-18 |
Family
ID=22993715
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000608982A Expired - Lifetime CA1306502C (en) | 1988-10-21 | 1989-08-22 | Simulcast broadcasting system and method |
| CA000616300A Expired - Fee Related CA1316985C (en) | 1988-10-21 | 1992-01-28 | Simulcast broadcasting system and method |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000616300A Expired - Fee Related CA1316985C (en) | 1988-10-21 | 1992-01-28 | Simulcast broadcasting system and method |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0439515A4 (en) |
| AU (1) | AU620939B2 (en) |
| BR (1) | BR8907727A (en) |
| CA (2) | CA1306502C (en) |
| WO (1) | WO1990004889A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5201061A (en) * | 1990-07-23 | 1993-04-06 | Motorola, Inc. | Method and apparatus for synchronizing simulcast systems |
| US5768260A (en) * | 1993-06-02 | 1998-06-16 | Telefonaktiebolaget Lm Ericsson | Device for changing the transmission parameters in a radio transmitter |
| TW449983B (en) * | 1998-12-21 | 2001-08-11 | Intel Corp | Data broadcast error sampling |
| DE19918829A1 (en) * | 1999-04-22 | 2000-10-26 | Deutsche Telekom Ag | Quality control method for digital radio broadcasting transmission by correcting bit error below threshold |
| FR2927756B1 (en) * | 2008-02-19 | 2010-06-18 | Tdf | SYNCHRONOUS DATA TRANSMISSION NETWORK AND METHOD OF MONITORING SUCH A NETWORK. |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4255814A (en) * | 1977-07-15 | 1981-03-10 | Motorola, Inc. | Simulcast transmission system |
| US4188582A (en) * | 1978-04-10 | 1980-02-12 | Motorola, Inc. | Simulcast transmission system having phase-locked remote transmitters |
| US4317220A (en) * | 1979-02-05 | 1982-02-23 | Andre Martin | Simulcast transmission system |
| US4317217A (en) * | 1980-08-11 | 1982-02-23 | Motorola, Inc. | Tag generator for a same-frequency repeater |
| US4363129A (en) * | 1980-12-11 | 1982-12-07 | Motorola, Inc. | Method and means of minimizing simulcast distortion in a receiver when using a same-frequency repeater |
| US4570265A (en) * | 1981-11-23 | 1986-02-11 | Motorola, Inc. | Random frequency offsetting apparatus for multi-transmitter simulcast radio communications systems |
| US4475246A (en) * | 1982-12-21 | 1984-10-02 | Motorola, Inc. | Simulcast same frequency repeater system |
| US4578815A (en) * | 1983-12-07 | 1986-03-25 | Motorola, Inc. | Wide area coverage radio communication system and method |
| FI71452C (en) * | 1985-04-10 | 1986-12-19 | Arvo Mustonen | SYNKRONISERINGSFOERFARANDE FOER ETT LOKALT T EX RIKSOMFATTANDEPERSONSOEKARNAETS RADIOSAENDARE |
| US4696052A (en) * | 1985-12-31 | 1987-09-22 | Motorola Inc. | Simulcast transmitter apparatus having automatic synchronization capability |
| US4718109A (en) * | 1986-03-06 | 1988-01-05 | Motorola, Inc. | Automatic synchronization system |
-
1989
- 1989-08-22 CA CA000608982A patent/CA1306502C/en not_active Expired - Lifetime
- 1989-09-22 BR BR898907727A patent/BR8907727A/en unknown
- 1989-09-22 EP EP19890912074 patent/EP0439515A4/en not_active Withdrawn
- 1989-09-22 WO PCT/US1989/004059 patent/WO1990004889A1/en not_active Application Discontinuation
- 1989-09-22 AU AU44853/89A patent/AU620939B2/en not_active Ceased
-
1992
- 1992-01-28 CA CA000616300A patent/CA1316985C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| AU620939B2 (en) | 1992-02-27 |
| WO1990004889A1 (en) | 1990-05-03 |
| AU4485389A (en) | 1990-05-14 |
| EP0439515A1 (en) | 1991-08-07 |
| CA1316985C (en) | 1993-04-27 |
| EP0439515A4 (en) | 1992-03-18 |
| BR8907727A (en) | 1991-07-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |