JPH04263529A - Fm-fdm transmission system - Google Patents

Abstract

PURPOSE:To obtain an economical multi-channel FM tuner by temporarily converting a block, where a desired channel exists, to the frequency of a 12GHz band and using a down converter and the FM tuner for following channel operations. CONSTITUTION:A prescribed space is required between the blocks for using the existent BS converter and BS tuner, and the fourth block is coincident with the frequency arrangement of a BS-1. A block converter 15 is composed of a mixer 12, variable frequency generator 13 and BPF 14. A BS converter 16 converts the 12GHz band to a 1GH band as a BS-1F. After the frequency conversion to the 12GHz for the unit of the block by the converter 15, a signal processing can be realized by the completely same constitution as the receiver of a 12GHz band television broadcasting due to communication satellites or broadcasting satellites. Further, the BS converter 16 and a BS tuner 8 can utilize the existent tuner for satellite broadcasting reception.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency array method in an FM-FDM optical analog transmission system for frequency multiplexing FM modulated signals.

0002

2. Description of the Related Art Conventionally, as a tuner for multi-channel FM-FDM signals, there is a block selection type tuner which selects a block of a fixed number of channels and then further selects a desired channel. FM-FDM applying this
Since the signal frequency arrangement requires a plurality of frequency generation circuits, there is a problem in that it becomes expensive. The prior art and its problems will be explained below using specific examples.

Development is progressing on a subcarrier optical transmission system in which a large number of carriers are frequency division multiplexed (FDM) in an electrical stage, a semiconductor laser is intensity modulated by the multiplexed electrical signal, and the signal is transmitted through an optical fiber. [Reference: Yoneda et al. “Trends in microwave subcarrier technology using optical fiber transmission” IEICE Microwave Research Group Proceedings (1990)]. F as the subcarrier modulation format
In an FM-FDM subcarrier optical transmission system using M, it is possible to transmit video signals of several tens of channels or more. In an FM-FDM video distribution system to which this transmission technology is applied, it is necessary to define and select a frequency array ranging from several tens of MHz to a GHz band.

An example of a frequency arrangement of an FM-FDM signal according to the prior art is shown in FIGS. 4 and 5. In Figure 4 (
A) shows the block arrangement, and (b) shows the local oscillation frequency for block selection. This is an example where 8 x 5 channels are frequency division multiplexed, with 8 channels per block, based on the current number of satellite broadcasting channels. It is. In this embodiment, channels 25 to 32 of the fourth block are the 1st channel of satellite broadcasting.
Matches the IF frequency array. FM with this frequency arrangement
- An example of the configuration of a multi-channel FM tuner for receiving FDM signals is shown in FIG.

1 is an FM-FDM signal input terminal, 2 and 5 are mixers, 3 is a variable frequency generator, 4 and 7 are band pass filters, 6 is a fixed frequency generator, and 8 is commonly known as 12 GHz.
FM tuner for receiving 12 GHz band television satellite broadcasts (after receiving the 12 GHz band television signal from the satellite with the antenna, it is tuned to the IF band (BS-IF) using a converter near the antenna.
) is input into a tuner equivalent to 8, so 8 is actually 1 GHz.
GHz band tuner), 9 is a tuning data input terminal,
10 is a baseband output terminal. 2 mixers, 3 variable frequency generators, and 4 bandpass filters constitute 11 block converters.

[0006] This multi-channel FM tuner operates as follows. FIG. 7 shows the channel selection process in this tuner. Figure 4 and Figure 5 to the input terminal of 1.
When an FM-FDM signal is input, first, the block in which the desired channel is arranged is converted to an RF frequency band of 6 GHz, which is higher than the highest frequency of the FM-FDM signal, by mixer 2 and variable frequency generator 3. Convert frequency. 4 is a bandpass filter that passes only the selected block signal. Next, the output signal of the band pass filter No. 4 is processed by the mixer No. 5 and the fixed frequency generator No. 6 at 12G.
1st IF band (1G) of Hz-band television satellite broadcasting
Hz band). After spurious components are removed by a bandpass filter 7, the signal is input to an FM tuner 8 for 12 GHz band television satellite broadcast reception, where a desired channel is selected and FM demodulated to obtain a baseband signal. In this configuration, by interlocking the 11 block converters and the 8 FM tuners, it is possible to select any channel from among the FM-FDM signals. The oscillation frequency (f1st-LO) of the No. 6 fixed frequency generator is 5.000 GHz, and the frequency (fLo) of the No. 3 variable frequency generator for selecting each block is as shown in FIG.

[0007] In this conventional configuration, it is necessary to develop new components except for the FM tuner for receiving 12 GHz television satellite broadcasting in the 8 GHz band, which increases the price. It is not the optimal frequency arrangement.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and its object is to provide an efficient frequency arrangement that reduces the cost of a receiving device.

[0009]

[Means for Solving the Problems] A feature of the present invention is that in the frequency arrangement of multi-channel FM-FDM signals, a plurality of blocks each having a set of a certain number of channels are arranged on the frequency axis, and one In the frequency arrangement method in which the blocks match the frequency arrangement of the 1st intermediate frequency band of 12 GHz band television broadcasting by communication satellites or broadcasting satellites, the configuration of the channel selection circuit on the receiving side is changed to the block in which the desired channel exists. , once the 12GHz of 12GHz band television broadcasting by communication satellite or broadcasting satellite
Frequency conversion to Z band and subsequent channel selection operation,
It is a multi-channel FM-FDM transmission system in which frequencies are arranged so as to be carried out using a down converter for receiving commercial 12 GHz band television broadcasting by a communication satellite or a broadcasting satellite, and an FM tuner.

0010

[Operation] The present invention is an FM-FDM signal frequency arrangement method in which a plurality of blocks each having a fixed number of channels are arranged, and the channel selection circuit can be used for receiving 12 GHz band television satellite broadcasting by existing broadcasting satellites or communication satellites. Arrange the circuit components so that they can be applied. This frequency arrangement allows the use of inexpensive consumer parts, making it possible to economically realize a multi-channel FM tuner.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a frequency arrangement of an FM-FDM signal according to the present invention is shown in FIGS. 1 and 2. Due to the use of existing BS converters and BS tuners, a predetermined interval is required between blocks. The fourth block is BS-IF
matches the frequency array of . FM-FD of this frequency arrangement
FIG. 3 shows an example of the configuration of a multichannel FM tuner for receiving M signals. Fifteen block converters are configured by 12 mixers, 13 variable frequency generators, and 14 bandpass filters. 16 is a 12 GHz band television satellite broadcast reception converter (12 GHz band B
The oscillation frequency is 10.678 GHz. The frequencies in the block converter are as shown in FIG. The operating principle of the tuner is exactly the same as that of the conventional frequency array tuner described above, but in the tuner of the present invention, the signal processing after frequency conversion to the 12 GHz band in units of blocks by 15 block converters. This can be realized with exactly the same configuration as an existing receiving device for 12 GHz band television broadcasting by a communication satellite or a broadcasting satellite. FIG. 8 shows the process of channel selection in a frequency array according to the present invention. Note that the BS converter 16 that is installed on the back of an existing satellite broadcast receiving antenna is sufficient, and the BS tuner 8 can also use an existing satellite broadcast receiving tuner.

The frequency array of the present invention is 16 12 GHz
This frequency arrangement differs from the conventional frequency arrangement in that it is determined by taking into consideration the frequency of 10.678 GHz, which is the frequency of the band television satellite broadcast reception converter.

In addition, the 12 mixers and 13 variable frequency generators, which are the main components of the block converter section, are constructed using microwave integrated circuit (MMIC) technology [Reference: Ohira et al.
AsMMIC/SiLSI Frequency Synthesizer” IEICE Microwave Study Group Proceedings No. MW-9
0-98 (1990)] can be applied, and miniaturization is possible.

[0014]

[Effects of the Invention] As explained above, according to the present invention,
Economical multi-channel F that can utilize existing inexpensive circuit components
M tuner can be realized.

Furthermore, the frequency array according to the present invention is not limited to the FM modulation method as a signal modulation method;
FSK is also used for M modulation method and for digital signals.
The present invention can be applied to FDM signals using any other carrier modulation method such as a modulation method or a PSK modulation method.

[Brief explanation of the drawing]

FIG. 1 shows an example of a frequency array according to the invention.

FIG. 2 shows an example of a frequency array according to the invention.

FIG. 3 is a configuration example of an FM-FDM signal tuner based on the frequency arrangement of the present invention.

FIG. 4 shows a conventional frequency arrangement.

FIG. 5 shows a conventional frequency arrangement.

FIG. 6 is a configuration example of an FM-FDM signal tuner using a conventional frequency arrangement.

FIG. 7 is an explanatory diagram of channel selection in a conventional multi-channel FM tuner.

FIG. 8 is an explanatory diagram of channel selection in a multi-channel FM tuner according to the present invention.

[Explanation of symbols]

1 FM-FDM signal input terminal 2 Mixer 3 Variable frequency generator 4 Bandpass filter 5 Mixer 6 Fixed frequency generator 7 Bandpass filter 8 FM tuner for satellite broadcast reception 9 Tuning data input terminal 10 Baseband output terminal 11 Block Converter 12 Mixer 13 Variable frequency generator 14 Band pass filter 15 Block converter 16 Satellite broadcast reception converter

Claims (2)

[Claims] Claim 1: A frequency arrangement of a multi-channel FM-FDM signal, in which a plurality of blocks each having a set of a certain number of channels are arranged on the frequency axis, and one block has the following characteristics:
In the frequency arrangement method that matches the frequency arrangement of the 1st intermediate frequency band of 12 GHz band television broadcast by communication satellite or broadcasting satellite, the configuration of the channel selection circuit on the receiving side is changed to the block where the desired channel exists.
Once the frequency is converted to the 12 GHz band of the 12 GHz band television broadcast by a communication satellite or broadcasting satellite, the subsequent channel selection operation is performed using a down converter for receiving commercial 12 GHz band television broadcasting by a communication satellite or broadcasting satellite, and an FM tuner for the same. A multi-channel FM-FDM characterized in that frequencies are arranged in a configuration using
Transmission method. 2. A multi-channel FM tuner that selects an arbitrary channel using an FM-FDM signal according to the frequency arrangement, comprising: an up-converter that converts the frequency to a 12 GHz band in block units; and a 12 GHz band television provided by a communication satellite or a broadcasting satellite. FM characterized by having a down converter for broadcast reception and an FM tuner
-FDM receiver.