JPH11122131A - Mixing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixing system capable of mixing two signals duplicate in frequency. SOLUTION: A 1st input signal S(CS-IF) is frequency-converted into a frequency band different from that of the 1st input signal S(CS-IF), and a 1st frequency conversion signal SCS1 subjected to frequency conversion is converted into a frequency band that differs from that of the 1st frequency conversion signal SCS1 and from that of a 2nd input signal S(BS-IF). Thus, the frequency band of the 1st input signal S(CS-IF) and the 2nd input signal S(BS-IF) is converted into a different frequency band and then the two input signals are mixed and the mixed signal is sent through one cable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order.

BACKGROUND OF THE INVENTION Problems to be Solved by the Invention (FIG. 4) Means for Solving the Problems Embodiments of the Invention (FIGS. 1 to 3) Effects of the Invention

[0003]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixing apparatus, and more particularly, to a mixing apparatus suitable for mixing satellite broadcast reception signals.

[0004]

2. Description of the Related Art In recent years, television broadcasts use a VHF (Very High Frequency) band as a frequency band (hereinafter referred to as VHF broadcast) and UHF (Ultra High Fr).
In addition to terrestrial broadcasting such as broadcasting using an equency band (hereinafter referred to as UHF broadcasting), satellite broadcasting by a broadcasting satellite (BS: Broadcasting Satellite) for broadcasting is performed. Satellite broadcasting radiates broadcast waves from geostationary satellites above the equator, so it can reliably transmit broadcast waves to mountainous areas and remote islands, and since there are no obstacles in radio wave propagation, there are problems such as ghost and beat interference. There is an advantage that a high quality image can be obtained because there is no image.

[0005] In addition to the BS broadcasting by the broadcasting satellite, a CS broadcasting using a communication satellite (CS) is newly started, whereby two broadcastings, a BS broadcasting and a CS broadcasting, are performed as satellite broadcasting. It has become.

[0006]

As shown in FIG. 4, the transmission frequency band of the BS broadcast wave received by the antenna is converted to 1032 to 1335 [MHz] in the BS broadcast, and the CS antenna is converted to the CS antenna in the CS broadcast. Since the transmission frequency band of the received CS broadcast wave is frequency-converted to 1050 to 1550 [MHz], the transmission frequency bands overlap, and the received BS broadcast wave and CS
When a broadcast wave is transmitted using the same cable, the signal waves of the two interfere with each other.

For this reason, for example, BS broadcasting, VHF and U
In the case of HF broadcasting, the signals transmitted are transmitted using the same cable because the transmission frequencies are distant from each other, and in the case of receiving CS broadcasting, a cable different from the cable transmitting the received signal of BS broadcasting must be used. Must be used for transmission. Therefore, in order to take the CS broadcast reception signal from an outdoor antenna to an indoor tuner via a cable,
When a new CS cable is laid in addition to the already laid BS cable, there is a problem that complicated laying work is required.

The present invention has been made in view of the above points, and has as its object to propose a mixing device capable of mixing two signals having mutually overlapping frequencies.

[0009]

According to the present invention, in order to solve such a problem, a first input signal is frequency-converted into a frequency band different from the frequency band of the first input signal,
The frequency-converted first frequency-converted signal is converted to the first frequency-converted signal.
By converting the frequency band of the first input signal and the frequency band of the second input signal into different frequency bands by converting the frequency band different from the frequency band of the frequency conversion signal and the frequency band different from the frequency band of the second input signal. Thus, the two input signals can be mixed and transmitted over one cable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a receiving system for receiving satellite broadcasts and terrestrial broadcasts as a whole, and is a 12-GHz band BS broadcast wave radiated to the ground by relaying a broadcasting satellite (BS). After being received by the BS antenna 6, the EW _BS is transmitted by the BS converter 6A provided in the BS antenna 6 to the 1 GHz band (1032 to 1032).
The frequency is converted to a BS intermediate frequency signal S (BS-IF) of 1335 [MHz]. The BS intermediate frequency signal S (BS-IF) is input to the BS input terminal 8A of the mixer 8 via the coaxial cable 7.

[0012] In addition, VHF emitted from the ground of broadcasting facilities (including repeaters) (Very High Frequency) band of terrestrial (television broadcast wave) EW _V and UHF (Ultra High
Frequency) terrestrial wave (television broadcast wave) EW
_U is by connexion received by the terrestrial antenna 9, TV in the VHF band (90~222 [MHz]) Ji received signal S _V and UH
F zone via the coaxial cable 10 as a television receiver signal S _U in (470~770 [MHz]) is inputted to the terrestrial input terminal 8B of the mixer 8. The mixer 8 is provided outdoors relatively close to the BS antenna 6 and the terrestrial antenna 9.

Here, a BS intermediate frequency signal S (BS-IF) obtained through a BS converter 6A and television reception signals S _V and S _U obtained through a terrestrial antenna 9 are used.
Means that different frequency bands are assigned to each other, so that the mixer 8 mixes them and
1 can be input to a first input terminal 12 of a single-shaft transmission mixer 4 as a mixing device according to the invention.

On the other hand, a communication satellite (CS: Communic)
ations Satellite) and radiated to the ground 12 [GH
After the CS broadcast wave EW _CS of the z] band is received by the CS antenna 2, the 1 GHz band (1050 to 1550 [MHz]) is received by the CS converter 2 A provided in the CS antenna 2.
Is converted to a CS intermediate frequency signal S (CS-IF). The CS intermediate frequency signal S (CS-IF) is input to the second input terminal 5 of the single-shaft transmission mixer 4 via the coaxial cable 3.
The single-axis transmission mixer 4 includes each antenna (BS antenna 6, terrestrial antenna 9 and C
It is installed outdoors relatively close to the S antenna 2).

Here, the frequency band (1050 to 1550 [MHz]) of the CS intermediate frequency signal S (CS-IF) input to one input terminal 5 of the single-axis transmission mixer 4 is Of the BS intermediate frequency signal S (BS-I
F) overlaps with the frequency band (1032-1335 [MHz]). Therefore, the single-axis transmission mixer 4 converts the CS intermediate frequency signal S (CS-IF) input to the input terminal 5 into the received signals (intermediate frequency signal S (BS-IF), By performing frequency conversion to a frequency band different from the frequency band of the television reception signals S _V and S _U ), each of these reception signals (intermediate frequency signal S (CS-IF), intermediate frequency signal S (BS-IF), The television reception signals S _V and S _U ) are mixed and transmitted on one axis.

That is, in FIG.
Is a CS intermediate frequency signal S (CS-I
F) is input to the first-stage mixer 31. The mixer 31 multiplies a CS intermediate frequency signal S (CS-IF) by a signal of frequency 1950 [MHz] (hereinafter referred to as a first local signal) S _L1 obtained from a local oscillator 32 to thereby generate a CS intermediate signal. frequency signal S (CS-IF) frequency (1050 ~1550 [MHz]) and of the difference between the frequency of the local signal S _L1 (1950 [MHz]) frequency (4
A low-frequency signal (down-convert component) consisting of 00 to 900 [MHz] is generated, and a low-pass filter (LP)
F) Send to 33.

The low-pass filter 33 extracts only the down-convert component (400 to 900 [MHz]) and sends it to the succeeding amplifier circuit 34 as the first-stage frequency conversion signal S _CS1 . Therefore, as shown in FIG. 3 (A), 1050 to 1550 [MHz]
CS intermediate frequency signal S (CS-IF) having a frequency of 400 to 90
The frequency is converted to a first frequency conversion signal S _CS1 of 0 [MHz] and input to the amplifier circuit 34. Incidentally, the first frequency converted signal S _CS1 overlaps with the band of the television receiver signal S _U in the UHF band.

The amplification circuit 34 amplifies the first-stage frequency conversion signal _SCS1 to a predetermined level, and sends the signal to the low-pass filter 35. The low-pass filter 35 outputs the first-stage frequency-converted signal S amplified by the amplifier circuit 34.
The noise component of _CS1 is removed, and the following second-stage mixer 36
To send to.

The mixer 36 multiplies the first-stage frequency conversion signal S _CS1 by a local signal S _L2 having a frequency of 2295 [MHz] obtained from the local oscillator 37, thereby obtaining the first-stage frequency conversion signal S _CS1 . the difference between the frequency of the _CS1 frequency (400~900 [MHz]) and the frequency of the local signal _{S L2 (2295 [MHz])} (1
395 to 1895 [MHz]). This signal is sent to the output terminal 13 of the single-shaft transmission mixer 4 via a high-pass filter (HPF) 38 which follows as a second-stage frequency conversion signal S _CS2 . Thus Figure 3 as shown in (B), 400 ~900 second made at a frequency of [MHz] frequency converted signal S _CS1 of the first stage comprising a frequency of 1,395 to 1,895 [MHz]
The frequency is converted into the frequency conversion signal S _CS2 of the first stage and transmitted to the output terminal 13. Incidentally, the second frequency conversion signal S _CS2 has a band of the television reception signal S _{U in} the UHF band, a band of the television reception signal S _{V in} the VHF band, and a band of the BS intermediate frequency signal S (BS-IF). It is a band that does not overlap any of them and the BS intermediate frequency signal S (BS-I
The band is separated by 60 [MHz] from the upper limit frequency (1335 [MHz]) of F). Also, the upper limit frequency 1895 [MHz] of the second-stage frequency conversion signal S _CS2 is a frequency that substantially matches the upper limit frequency that can be supported by a distributor and a tuner described later.

In response to the CS intermediate frequency signal S (CS-IF), the BS intermediate frequency signal S (BS-IF) input to the first input terminal 12 of the single-axis transmission mixer 4 and the television reception signal S _V and S _U are sent to the output terminal 13 via the low-pass filter 40. Thus, from the output terminal 13 of the uniaxial transmission mixer 4, the BS intermediate frequency signal S (BS-IF), the VHF band television reception signal S _V , the UHF band television reception signal S _U, The converted CS intermediate frequency signal (second-stage frequency converted signal S _CS2 ) is mixed (S13) and output via the same coaxial cable.

The BS intermediate frequency signal S (BS-IF) mixed and output from the output terminal 13 of the single-axis transmission mixer 4 in this manner.
, The VHF band television reception signal S _V , the UHF band television reception signal S _U, and the frequency-converted CS intermediate frequency signal (second-stage frequency conversion signal S _CS2 ) are shown in FIG.
Are transmitted to a distributor 15 provided indoors via a coaxial cable 14 shown in FIG.

The distributor 15 converts the frequency of the BS intermediate frequency signal S (BS-IF), the VHF band television reception signal S _V , the UHF band television reception signal S _U sent from the single-axis mixer 4, and frequency conversion. A signal obtained by mixing the CS intermediate frequency signal (second-stage frequency conversion signal S _CS2 ) is divided into two systems, one of which is connected to the output terminal 15A via the coaxial cable 16 via the CS.
The signal is sent to the tuner 17, and the other is sent from the output terminal 15 </ b> B to the duplexer 20 via the coaxial cable 19.

The CS tuner 17 is mixed reception signal (BS intermediate frequency signal S (BS-IF), VHF band television reception signal S _V, the UHF band television reception signal S _U and the frequency-converted CS intermediate frequency signals First, a frequency-converted CS intermediate frequency signal (frequency-converted signal S _CS2 ) is extracted from (second-stage frequency-converted signal S _CS2 )), amplified, and then selected by a user operation. It takes out a video signal CS _V corresponding to been channel, PC
By performing phase detection on the sound of an M (Pulse Code Moulation) signal, the analog sound signal CS is converted from the digital signal.
Convert to _A and take out. The video signal CS _V and the audio signal CS _A thus extracted are sent to the video / audio signal input terminal 24 of the television receiver 21 and displayed in a display form according to the operation of the user.

Incidentally, the CS tuner 17 supplies a power Vc for operating the single-shaft transmission mixer 4, the CS converter and the BS converter via coaxial cables 16, 14, 11, 7 and 3. Further, in this receiving system 1, by transmitting a polarization switching signal and a satellite switching signal from the CS tuner 17 to the CS antenna 2 through the uniaxial transmission mixer 4, the dual beam antenna is used as the CS antenna 2. Is different 2
It can switch and receive horizontally or vertically polarized CS broadcast waves radiated from one communication satellite (CS).

On the other hand, the splitter 20 receives the mixed reception signal (BS intermediate frequency signal S (BS-IF), V
The HF band television reception signal S _V , the UHF band television reception signal S _U, and the frequency-converted CS intermediate frequency signal (second-stage frequency conversion signal S _CS2 ) are converted to a BS intermediate frequency signal S (BS− IF), extracts the television reception signal S _V and the television receiver signal S _U in the UHF band in the VHF band, BS intermediate frequency signal S (BS-IF) the first output terminal 20
It sends out the BS signal input terminal 21A of the television receiver 21 having a BS tuner through a coaxial cable 22 from the A, via a coaxial cable 23 to the television receiver signal S _V and S _U of the VHF band and UHF band VHF / UHF input terminal 21B of television receiver 21
To enter.

The television receiver 21 has a BS intermediate frequency signal S (BS-IF) input via a BS signal input terminal 21A.
After amplification to a predetermined level, takes out a video signal and an audio signal corresponding to the channel that had it occurred selected with the operation of the user, the television receiver signal input through the VHF / UHF input terminal 21B S _V and S _U The video signal and the audio signal corresponding to the channel selected by the user are taken out of the above and displayed in a display form according to the operation of the user.

The CS intermediate frequency signal S (CS-IF) (1050 to CS) of the CS broadcast obtained through the CS converter 2A in this manner.
1550 [MHz]) is frequency-converted to an intermediate frequency signal of 1395 to 1895 [MHz] (second-stage frequency conversion signal S _CS2 ) by two-stage frequency conversion in the single-axis transmission mixer 4. , BS intermediate frequency signal S (BS-IF), television reception signals in the VHF band S _V, UHF band television reception signal S _U and the frequency-converted CS intermediate frequency signal (second-stage frequency conversion signal S _CS2 ) does not have overlapping frequency bands, and as a result, each received signal can be transmitted using the common coaxial cable 14.

Here, in the receiving system 1, CS
As the CS converter 2 </ b> A provided in the antenna 2, those having various values of the local frequency (frequency of the local oscillator) can be used. In this case, if the local frequency of the CS converter 2A is different,
CS whose frequency has been converted by the CS converter 2A
The frequency of the intermediate frequency signal S (CS-IF) will also be different.

In the case of this embodiment, the CS converter 2
The local frequency of A is 11.2 [GHz], and the frequency of the CS intermediate frequency signal S (CS-IF) converted by this local frequency is 1050 to 1550 [MHz]. On the other hand, an intermediate frequency signal obtained by subjecting the CS intermediate frequency signal S (CS-IF) to frequency conversion by the uniaxial transmission mixer 4 (the second stage frequency conversion described above with reference to FIG. 2). The frequency of the signal S _CS2 ) is 1395 to 1895 [MHz], and C
The S channel 17 can select the CS channel of the channel set by the user for any intermediate frequency signal.

That is, when the CS intermediate frequency signal S (CS-IF) obtained from the CS converter 2A is input to the CS tuner 17 without using the single-axis transmission mixer 4, the CS converter provided in the CS tuner 17 By setting the set frequency of the frequency setting means (not shown) to 11.2 [GHz], the frequency band (1050) of the CS intermediate frequency signal S (CS-IF) is set.
~ 1550 [MHz]) can be selected for each channel.

On the other hand, the CS intermediate frequency signal S (CS-IF) obtained from the CS converter 2A is converted to a frequency of 1395 to 1895 [MHz] through the single-axis transmission mixer 4 and is transmitted to the CS tuner 17. If input, the frequency converted CS
The frequency of the intermediate frequency signal (S _CS2 ) has a difference of 345 [MHz] from the above-mentioned CS intermediate frequency signal S (CS-IF) which is not frequency-converted. Therefore, in this case, the set frequency of the CS converter frequency setting means (not shown) of the CS tuner 17 is 10.855 [MHz] obtained by subtracting 345 [MHz], which is the frequency conversion of the CS intermediate frequency signal, from the above 11.2 [GHz]. ], The frequency of each channel recognized by the CS channel 17 is shifted in accordance with the CS converter set frequency (10.855 [MHz]) at this time, whereby the frequency is converted by the single-axis transmission mixer 4. Each channel assigned to the CS intermediate frequency signal (frequency conversion signal S _CS2 ) is selected by a user's selection operation in the same manner as when the CS converter frequency is 11.2 [GHz].

In general, when the frequency of an intermediate frequency signal is converted by multiplying an intermediate frequency signal and a local signal in a mixer, an arrangement on the frequency of the channel allocated to the converted intermediate frequency signal is performed. However, as described above with reference to FIG. 2, by performing two-stage frequency conversion in the single-shaft transmission mixer 4, C
The arrangement of the channels allocated to that frequency band in the S intermediate frequency signal S (CS-IF) returns to the same arrangement in the second-stage frequency conversion signal S _CS2 . Therefore, CS Cheuna 1
In 7, each channel allocated to the CS broadcast wave can be selected only by changing the set frequency of the CS converter frequency setting means.

In the above configuration, the C antenna 2
CS intermediate frequency signal S obtained in S converter 2A
(CS-IF) is frequency-converted twice by mixers 31 and 36 of single-axis transmission mixer 4.

In this case, the CS intermediate frequency signal S (CS-IF) overlapping the frequency band of the BS intermediate frequency signal S (BS-IF) is converted to the frequency band (4) overlapping the UHF band by the first frequency conversion.
00 to 900 [MHz]), and by the second frequency conversion, the BS intermediate frequency signal S (BS-IF), VHF band and UHF
It is converted into a frequency band that does not overlap with each of the television reception signals S _V and S _{U in} the band.

The frequency band (1395 to 1895 [MHz]) obtained by the second frequency conversion is the frequency band (1050 to 1550 [MHz]) before frequency conversion obtained from the CS converter 2A.
Although the frequency bands before and after the first frequency conversion (1050-1550 [MHz] and 400-900 [MHz]) do not overlap each other, the frequency bands before and after the second frequency conversion
(400 to 900 [MHz] and 1395 to 1895 [MHz]) are also bands that do not overlap each other, so that the second-stage frequency converted signal S from the CS intermediate frequency signal S (CS-IF) whose frequency bands overlap each other. Frequency conversion to _CS2 becomes possible.

In the single-axis transmission mixer 4 provided outdoors as described above, another received signal (BS intermediate frequency signal S (B
S-IF), a CS intermediate frequency signal (second-stage frequency conversion signal S _CS2 ) converted into a frequency band that does not overlap with any of the television reception signals S _V and S _U in the VHF band and the UHF band. Is mixed with each received signal and supplied to a distributor 15 provided indoors via one coaxial cable 14.

Accordingly, for example, the BS intermediate frequency signal S (BS-I
F) If a single-axis transmission mixer 4 is added to a conventional receiving system adapted to take in the television reception signals S _V and S _U of the VHF band and the UHF band indoors using one coaxial cable 11, In addition, only the coaxial cable 14 connected to the uniaxial transmission mixer 4 from the cable laid outdoors to indoors is used. As a result, without increasing the number of coaxial cables laid from outdoors to indoors, the CS intermediate frequency signal (S
_CS2 ) can be taken indoors, and additional laying work accompanying the increase in cables can be avoided.

According to the above configuration, each received signal (BS intermediate frequency signal S (BS-IF), frequency-converted CS intermediate frequency signal (S _CS2 ), VHF band, and UHF By mixing the television reception signals S _V and S _U ) of the band, each reception signal can be transmitted using one coaxial cable 14, and the configuration of the reception system 1 can be simplified. .

In the above embodiment, a case has been described in which a desired frequency band is obtained by frequency-converting the CS intermediate frequency signal S (CS-IF) twice, but the present invention is not limited to this. Instead, various numbers of frequency conversions can be applied.

In the above-described embodiment, the case where the CS intermediate frequency signal S (CS-IF) is frequency-converted has been described. However, the present invention is not limited to this, and the BS intermediate frequency signal S (BS-IF) ) Can be widely applied to the case where the frequency is converted, or further various other received signals are frequency-converted and transmitted through the same cable.

[0041]

As described above, according to the present invention, the first input signal is frequency-converted to a frequency band different from the frequency band of the first input signal, and the frequency-converted first frequency-converted signal is converted. Is converted to a frequency band different from the frequency band of the first frequency-converted signal and different from the frequency band of the second input signal, so that the frequency bands of the first input signal and the second input signal are different from each other. And thus the two input signals can be mixed and transmitted over one cable.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an overall configuration of a receiving system according to the present invention.

FIG. 2 is a block diagram showing a configuration of a single-axis transmission mixer.

FIG. 3 is a schematic diagram for explaining frequency conversion of an intermediate frequency signal.

FIG. 4 is a schematic diagram illustrating a frequency band of each received signal.

[Explanation of symbols]

1 ... receiving system, 2 ... CS antenna, 3, 7, 1
0, 1, 14, 16, 19, 22 and 23 ... coaxial cable, 4 ... single-axis transmission mixer, 6 ... BS antenna,
8, 20: duplexer, 15: distributor, 17: CS tuner, 21: television receiver.

Claims (2)

[Claims] 1. A first input signal having a first frequency band and a second input signal having a frequency band overlapping the first frequency band.
A first frequency conversion means for frequency-converting the first input signal into a frequency band different from the frequency band of the first input signal; and a first frequency conversion means. Frequency conversion means for converting the first frequency-converted signal frequency-converted by the first frequency-converted signal into a frequency band different from the frequency band of the first frequency-converted signal and different from the frequency band of the second input signal. A mixing device comprising: 2. The first input signal is an intermediate frequency signal obtained by receiving a broadcast wave radiated from a communication satellite, and the second input signal is radiated from a broadcast satellite different from the communication satellite. The mixing device according to claim 1, wherein the mixing device is an intermediate frequency signal obtained by receiving a broadcast wave.