JPH0330589A - Satellite television transmission system - Google Patents

Abstract

PURPOSE:To realize the stable time division of a transmission carrier by using a satellite repeater by thining a television field signal attached with a start/stop signal to transmit as a burst-shaped signal while synchronizing and coupling the above mentioned signal with the transmission signal of its own station by a synchronizing signal added to a received color burst signal. CONSTITUTION:A master station A generates a burst-shaped transmission control signal during only short first time t1 at every field period of a television signal, and slave stations B and C transmit the television field signal in a burst-shaped form during only a second time t2 in an interval in which the above-mentioned transmission control signal does not exist on the satellite repeater P on the basis of the extracted transmission control signal. A base band signal demodulated by a receiver 5 is divided into three parts, and the start/stop signal is extracted from the television field signal by a start/stop signal extraction circuit 15 respectively, and other two devided signals are extracted by field signal B, C extraction circuits 6B and 6C, and in TV signal B, C interpolation circuits 7B and 7C, the lacked field signal is regenerated by line interpolation or field interpolation, and the television signal is restored.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a system for transmitting television signals from a plurality of slave stations to one master station by satellite relay. The present invention is 1
This invention relates to a satellite communication system that uses multiple satellite repeaters in a time-sharing manner.

〔overview〕

The present invention provides a system for transmitting television signals from a plurality of slave stations to one master station via a satellite repeater, in which the master station transmits a short transmission control signal for each field,
The slave station follows this transmission control signal and transmits television signals in bursts on the satellite repeater within the intervals of this transmission control signal, making it possible to easily control the satellite repeater in a time-division manner. It is.

[Conventional technology]

Traditionally, this type of multidimensional satellite television transmission system has used multiple satellite transponders. Furthermore, when one satellite repeater is used, the frequency is divided and two or more carriers are transmitted.

[Problem that the invention seeks to solve]

However, in the conventional system, when a plurality of satellite repeaters are used, the efficiency of satellite utilization deteriorates. Furthermore, when one satellite repeater is used with frequency division, interference and crosstalk occur between each carrier, and problems such as internal cross-modulation products occur when multiple carriers are amplified. There were drawbacks. Furthermore, when the satellite repeater is used in a state close to saturation, there is a possibility that carrier level imbalance may occur due to the small signal suppression effect.

SUMMARY OF THE INVENTION An object of the present invention is to solve these drawbacks and provide a satellite television transmission system that allows stable time division of transmission carriers using a satellite repeater and facilitates interpolation of broadcast image signals at the main station. .

[Means for solving problems]

The present invention includes a main station, a plurality of slave stations, and a satellite repeater that relays communication between the master station and the slave stations, and a means for transmitting television signals from the plurality of slave stations to the master station. In the satellite television transmission system, the master station includes means for transmitting a burst-like transmission control signal to each slave station via a satellite repeater for a short first period of time for each field period of the television signal, each of the plurality of slave stations includes means for decoding the outgoing control signal; and means for decoding the outgoing control signal on the satellite transponder based on the decoded outgoing control signal for a second period of time in the interval in which the burst outgoing control signal is not present. means for transmitting a television field signal, and the main station includes means for separating the television field signal from a signal received from the satellite repeater.

[Effect]

The main station transmits a television synchronization signal and a transmission control signal in bursts for each color burst signal. In a plurality of slave stations, the received color burst signal is synchronously combined with the transmission signal of the own station using an added synchronization signal, and the television field signal with start/stop signal is transmitted as a thinned-out Teherst signal. The timing of this transmission is controlled so that multiple signals do not overlap on the satellite repeater and are inserted between outgoing control signals. The main station detects the start/stop signal from the received television field signal with start/stop signal, and generates a transmission control signal so as not to overlap with the time-divided adjacent carrier. In addition, the thinned and received television field signal is interpolated with the signal between the preceding and following lines or the next received television field signal to reproduce the missing field signal.
Obtain a multidimensional television signal.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a configuration diagram of an embodiment of the present invention.

FIG. 1(a) is a block diagram of the main station A, and FIGS. 1(a) and 1(a) are block diagrams of the two slave stations B and C.

In FIG. 1(a), the main station A includes a color subcarrier signal generation circuit 1 that generates a subcarrier signal, a television synchronization signal generation circuit ``2'' that generates a synchronization signal including a color burst signal, and It includes a transmitter 4 that converts a synchronization signal and a transmission control signal into a master station transmission carrier 4A and transmits the same.Furthermore, a receiver 5 that receives each slave station transmission carrier 13B or 13C transmitted by slave stations B and C, Of the demodulated baseband signal 5A output from this receiver 5, a television field signal B of the slave station B and a television field signal C of the slave station C are selected.
A field signal B extraction circuit 6B and a field signal C extraction circuit 6C, which respectively extract include.

In addition, in FIG. 1(b), slave stations B and C use a receiver 8 that receives the master station transmission carrier 4A, and apply a genlock to the synchronization coupling circuit 10A of the television camera 10 from among the outputs of this receiver 8. The transmitter 13 includes a black burst signal detection circuit 9 that detects a black burst signal to be transmitted, and a transmitter 13 that transmits the television field signal sent out from the television camera IO to the satellite repeater P as a slave transmission carrier 13B or 13C.

FIG. 1C is a diagram of a transmission path through which the one master station A and the two slave stations B and C transmit and receive data via the satellite repeater P. In the figure, the broken line indicates the master station transmission carrier 4A containing the transmission control signal, the ζ solid line indicates the slave station transmission carrier 13B from the slave station B, and the dashed line indicates the slave station transmission carrier 13C from the slave station C.

Here, the feature of the present invention is that in the timing diagram of the transmitting and receiving carriers of the master station and slave station shown in FIG.
The main station A is equipped with a transmission control signal generation circuit 3 that generates a burst-like transmission control signal for a short first time t every field period of the television signal and manually inputs it to the television synchronization signal generation circuit 2, The slave stations B and C include a transmission control signal extraction circuit 11 for decoding the transmission control circuit code;
The outgoing control signal (transmitted for a first time t1) on the satellite repeater P based on this extracted outgoing control signal
The main station A is equipped with a transmission control circuit 12 that transmits television field signals in bursts for a second time t2 (see FIG. 2) at intervals when the main station A does not exist.
A start/stop signal extraction circuit 15 is provided for separating the television field signal received from the television field signal. Using the output of the color subcarrier signal generation circuit 1 as a source signal, a television synchronization signal generation circuit 2 generates a television synchronization signal to which a color burst signal is added. On the other hand, the baseband signal demodulated by the receiver 5 manually by the slave transmission carrier 13B or 13C is
The signal is branched into three, and a start/stop signal is extracted from the television field signal by a start/stop signal extraction circuit 15, respectively. The transmission control signal generation circuit 3 determines whether this start/stop signal is sent at the correct timing, encodes the transmission control signal, and the television synchronization signal generation circuit 2 generates a television synchronization signal with color burst. The transmitter 4 converts the baseband signal into the main station transmission carrier 4A as a baseband signal, and transmits it in bursts.

From the other two branches, each television field signal is extracted by field signal B extraction circuits 6B and 6C, respectively. In the television signal interpolation circuits 7B and 7C, the missing field signals are reproduced by line interpolation or field interpolation to restore the television signal.

At slave station B or C, baseband signal 8B is demodulated by receiver 8 by human power of main station transmission carrier 4A.
Or branch 8C into two. One signal is obtained by decoding the transmission control signal of the local station in the transmission control signal extraction circuit 11 and inputted to the transmission control circuit 12 manually.

The other signal is detected by the black burst signal detection circuit 9 as a color subcarrier signal and a television synchronization signal from the television synchronization signal with the color burst signal, and is sent to the synchronization coupling circuit 10A of the television camera IO.
is input to receive the genlock function. The genlocked television signal output is intermittently divided into two field signals by the transmission control circuit 12, thinned out, and input to the transmitter 13.

The transmitter 13 is further supplied with a transmission carrier intermittently from a transmission control circuit and transmits it in bursts.

FIG. 2 is a diagram showing the timing of transmission carriers in each station, and FIG. 3 is a waveform diagram of baseband signals generated internally at the main station and slave station B.

Here, the interval between the transmission bursts of the transmission carrier 4A of the main station A corresponds to the field time, and the burst duration time t1
almost corresponds to the vertical blanking interval. Further, the burst duration time t2 of slave station B corresponds to a video section within an even field or an odd field.

Also, in Figure 2, the transmission delay between each station is 1. ．． It is shown as 1°. By controlling the timing of transmission carriers in this manner, signal duplication on the repeater does not occur even if the relay distance changes.

〔Effect of the invention〕

As explained above, according to the present invention, when performing multi-channel television relay broadcasting between a plurality of earth stations via a single satellite repeater, the satellite repeater can be used in a time-sharing manner, thereby increasing its utilization efficiency. be able to.

Even if the distance between each earth station and the satellite repeater changes, the signals on the satellite repeater do not overlap. Since the synchronization system signal of the slave station is genlocked to the synchronization system of the master station, there is an advantage that the video signal interpolation process in the master station can be performed easily.

[Brief explanation of drawings]

1(a) and 1(a) are block configuration diagrams of a master station and a slave station according to an embodiment of the present invention, and FIG. 1(C) is a transmission path diagram. FIG. 2 is a timing diagram of each transmission carrier. FIG. 3 shows an example of baseband signals generated from each earth station. DESCRIPTION OF SYMBOLS 1... Color subcarrier signal generation circuit, 2... Television synchronization signal generation circuit, 3... Transmission control signal generation circuit, 4.13... Transmitter, 4A, 13B, 13C
...Respectively transmission carrier, 5.8...Receiver, 5
A. 8B, 8C...Baseband signal, 6B, 6C...
Field signal B extraction circuit and field signal C extraction circuit, 7B, 7C... Television signal B interpolation circuit and television signal C interpolation circuit, 9... Black burst signal detection circuit, 10... Television camera,
IOA: Synchronous coupling circuit, 11: Transmission control signal extraction circuit, 12: Transmission control circuit, 14: Start/stop signal, 15: Start/stop signal extraction circuit, A... Main station, B, C...Slave stations, P...Satellite repeater.

Claims (1)

[Scope of Claims] 1. A main station, a plurality of slave stations, and a satellite repeater that relays communication between the master station and the slave stations, and a television broadcast from the plurality of slave stations to the master station. In a satellite television transmission system including means for transmitting a signal, the main station is provided with a burst-like transmission control signal via the satellite repeater for a short first time (t_1) for each field period of the television signal. each of the plurality of slave stations includes means for decoding the transmission control signal and controlling the burst transmission on the satellite repeater based on the decoded transmission control signal. means for transmitting the television field signal in a burst form for a second time (t_2) during a signal-free interval, the main station transmitting the television field signal from the signal received from the satellite repeater; A satellite television transmission system characterized by comprising means for separating.