JPH0617389Y2 - Mixing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a mixing device provided between each terminal of a joint viewing device or pay television transmission device and an antenna terminal of a television receiver.

[Prior art]

Conventionally, in the joint hearing device and pay television transmission device,
In order to increase the number of television broadcasting signals to be transmitted, there is a case where so-called adjacent feeding is performed in which the television broadcasting signals are transmitted using adjacent frequency bands (channels). In such a case, each television signal is affected by the audio signal of the television signal in the lower frequency band to cause an audio beat failure in the image. Therefore, in order to prevent this, the television signal in each frequency band is prevented. It is performed that a voice signal of a signal is attenuated at a head end and then transmitted.

[Problems to be solved by the invention]

However, if the audio signal is attenuated and transmitted at the head end, there is a problem that when the television signal is received by the television receiver, the level of the audio signal is low and high-quality audio cannot be reproduced. In addition, in the pay television broadcasting device, a pay television signal is transmitted in addition to the broadcast television signal transmitted from the broadcasting station, but this pay television signal is different from the frequency band of the broadcast television signal. It may be converted into the frequency band of the broadcast television signal transmitted from the broadcasting station immediately before being transmitted in the frequency band and being supplied to the antenna terminal of the television receiver. If the broadcast television signal transmitted from the station and the frequency-converted version of the pay television signal are converted into the same frequency band, the pay television broadcasting cannot be received well, and there is a certain problem. When frequency conversion is performed to a frequency band above the frequency band of a broadcast television signal, this pay television signal is converted to a broadcast television signal. Produce a sound beat failure due to voice signal, there is a problem that can not be still be good receiver.

[Means for solving problems]

In order to solve the above problems, the present invention provides a television signal in a first frequency band that cannot be received by a television receiver and a television signal in a second frequency band that can be received by the television receiver. And at least have input and a distributor for distributing these television signals. Furthermore, when a signal distributed from this distributor is received and power is supplied to the converter unit power supply terminal, a television signal in the first frequency band is extracted from the distributor, and this is extracted into the second frequency band or this. It also has a converter section that performs frequency conversion into a television signal in the upper adjacent frequency band of (1) and stops the frequency conversion operation when power is not supplied to the converter section power terminal. Further, when a signal is received from the distributor and power is not supplied to the filter power supply terminal, the frequency characteristic is such that at least a television signal in the second frequency band is passed, and power is supplied to the filter power supply terminal. At this time, it also has a filter section having a frequency characteristic different from the above frequency characteristic. The different frequency characteristic is selected as a frequency characteristic that cuts off a television signal in the second frequency band when the converter unit converts the frequency into the second frequency band, and the converter unit converts the frequency into the upper adjacent frequency band. In this case, the frequency characteristic is selected so as to block the audio signal of the television signal in the second frequency band. It also includes a mixing unit that mixes the output signals of the converter unit and the filter unit, and a power switch that connects the interconnection point of the converter power source terminal and the filter power source terminal to an external power source.

[Action]

According to this invention, when the power switch is opened, no power is supplied to the converter section and the filter section, so that the converter section does not perform frequency conversion. as a result,
The filter section has frequency characteristics that allow at least the television signal in the second frequency band to pass. Therefore, the distribution output of the distributor including the television signal in the second frequency band is
It is supplied to the outside through the filter unit and the mixing unit. In this case, the television signal in the first frequency band is also supplied to the filter unit, but the television signal in the first frequency band is
Since it cannot be received by the television receiver as it is, no problem such as interference occurs. Further, since the filter section has a frequency characteristic of passing at least a television signal in the second frequency band, the distribution output includes a television signal that can be received by a television receiver other than the second frequency band. Also, these can be received by the television receiver.

In the state where the power switch is closed, power is supplied to the converter unit and the filter unit at the same time, the converter unit operates, and the television signal in the first frequency band included in one distribution output of the distributor is transmitted to the second signal. Frequency conversion to a television signal in the frequency band of or in the adjacent frequency band above. In addition, the filter unit includes the television signal of the second frequency band (when the converter unit converts the frequency to the second frequency band) or the television of the second frequency band included in the other distribution output of the distributor. The frequency characteristic cuts off the audio signal of the John signal (when the converter performs frequency conversion to the upper adjacent frequency band). Therefore, the television signal of the second frequency band or the audio signal thereof included in the other distribution output of the distributor is cut off, and the first one of the distribution outputs of the distributor is included. The television signal in the frequency band is mixed with the second frequency band or the one obtained by frequency-converting it into the upper adjacent frequency band, and the mixture is supplied to the outside. Does not happen. Moreover, even if the other distributed output includes television signals that can be received by the television receiver in a frequency band other than the second frequency band as they are, they pass through the filter section and are output to the outside. Even if the unit is operating, if the channel is switched by the television receiver so that the television signal other than the second frequency band can be received as it is, the Can be received.

〔Example〕

This embodiment has two distributors 2 as shown in FIG. The input terminal of the two-way divider 2 is connected to one terminal of the transmission line (not shown) of the pay television transmission device. This transmission path includes the one receiving the television broadcasting signal of the A frequency band forming the second frequency band transmitted from the broadcasting station with the antenna, and the first frequency band transmitted from the pay television broadcasting transmitter. The pay television signal of the B frequency band to be formed is transmitted at least. Therefore, a television broadcast signal transmitted from a broadcast station other than the A frequency band may be transmitted. The B frequency band is a frequency band far from the A frequency band and cannot be received even if it is directly supplied to the television receiver.

One of the divided outputs of the two-way divider 2, that is, a signal containing at least a television broadcast signal in both A and B frequency bands is supplied to the converter unit 4. The converter unit 4 does not operate when power is not supplied to the power supply terminal 6, and when power is supplied, the pay television signal in the B frequency band in the distribution output supplied from the 2 distributor 2 is supplied. Is C, which is one frequency band above the A frequency band.
The frequency is converted into a pay television signal in the frequency band and supplied to one input terminal of the mixing section 8.

The other distribution output of the two distributors 2, that is, at least A and B
A signal including a television broadcast signal in both frequency bands is supplied to the filter unit 10. This filter part 10
Is configured, for example, as shown in FIG. That is, the three capacitors 16, 18, 20 are connected in series between the input terminal 12 and the output terminal 14, and the capacitor 1
A series circuit of the reactor 22 and the voltage variable capacitance diode 24 is connected between the connection point of 6 and 18 and the reference potential point.
Similarly, a series circuit of the reactor 26 and the voltage variable capacitance diode 28 is connected between the connection point of the capacitors 18 and 20 and the reference potential point. These variable capacitance diodes 24, 2
High frequency blocking coils 30 and 32 are connected between 8 in series. The connection point of the high frequency blocking coils 30 and 32 is connected to the arm of the variable resistor 34, one end of this variable resistor 34 is grounded, and the other end is connected to the power supply terminal 36. In addition,
38, 39, 40 are bypass capacitors.

The filter section 10 is a high-pass filter, as is apparent from the frequency characteristics shown in FIGS. 3 and 4. Then, when power is not supplied to the power supply terminal 36, as shown in FIG.
The voltage variable capacitance diodes 24 and 28 are selected, and when the power is supplied, as shown in FIG. 4, the audio signal in the A frequency band is greatly attenuated and the capacity for passing the signal of a frequency higher than that is passed, The arm position of the variable resistor 34 is adjusted so that the capacitances of the voltage variable capacitance diodes 24 and 28 become equal to each other.

The output of the filter unit 10 is amplified by the amplification width 42 and supplied to the mixing unit 8. The output of the mixing section 8 is supplied to a television receiver (not shown).

Power supply terminal 6 of converter section 4 and power supply terminal of filter section 10
36 is connected, and its connection point is connected to a power source (not shown) via a power switch 44. Therefore, when the power switch 44 is open, power is not supplied to both the converter unit 4 and the filter unit 10, and the power switch is not supplied.
When the switch 44 is closed, power is supplied to both the converter unit 4 and the filter unit 10.

When the television receiver receives a television broadcast signal in the A frequency band, the power switch 44 is opened. As a result, the converter unit 4 does not operate, and even if a signal is transmitted from the two-way divider 2, the pay television signal in the B frequency band is not extracted and the frequency is not converted into the C frequency band. Further, the filter unit 10 has a frequency characteristic that allows the frequency above the lowest frequency in the A frequency band to pass. Therefore, the television broadcasting signal in the A frequency band supplied from the two-way divider 2 to the filter unit 10 passes through the filter unit 10,
The signal is amplified by the amplifier 42 and supplied to the television receiver via the mixer 8. At this time, the pay television signal in the B frequency band is also supplied to the television receiver,
Since the frequency band cannot be received by the television receiver, it does not affect the reception of the A frequency band. In addition,
If the A frequency band is selected as the lowest frequency band among the television broadcasting signals transmitted from each broadcasting station,
Since the filter unit 10 is a high-pass filter, other television broadcasting signals can be received with the power switch 44 opened.

When the television receiver receives a pay television signal in the B frequency band, the power switch 44 is closed. As a result, the converter unit 4 operates to extract a pay television signal in the B frequency band from the signals transmitted from the two-way divider 2 and convert it into a pay television signal in the C frequency band. As described above, the C frequency band is one frequency band higher than the A frequency band, and is in a so-called adjacent transmission state. If the frequency characteristic of the filter unit 10 is A
If the characteristic of allowing the signal to pass the lowest frequency of the frequency band or higher is maintained, the mixing section 8 mixes the television broadcast signal of the A frequency band and the pay television signal of the C frequency band and supplies the mixed signal to the television receiver. Therefore, when receiving a pay television signal in the C frequency band on a television receiver,
Audio beat failure occurs. However, the filter part is actually
Power is supplied to the filter 10, and the filter unit 10 passes only frequencies higher than the audio signal in the A frequency band. That is, the audio signal in the A frequency band is greatly attenuated. Therefore,
Since the mixing section 8 mixes the television signal in the C frequency band and the signal having a frequency higher than the audio signal in the A frequency band and supplies the mixed signal to the television receiver, the pay television signal in the C frequency band is converted into the television signal. Even if the signal is received by the receiver, the audio beat failure does not occur.

In the above embodiment, the filter unit 10 is a high-pass filter. However, when power is not supplied, frequencies below the audio signal in the A frequency band are passed, and when power is supplied, audio signals in the A frequency band are transmitted. A low pass filter configured to pass lower frequencies can also be used. In this case, in particular, if the A frequency band is selected as the highest frequency band among the television broadcasting signals transmitted from each broadcasting station, each television broadcasting signal can be received with the power switch 44 opened. . When the frequency band A is set to an intermediate frequency band between the television broadcasting signals and all the television broadcasting signals are to be received with the power switch 44 opened, the power is supplied to the filter unit 10. If not, a band elimination filter having a frequency characteristic of passing each television broadcast signal and a frequency characteristic of eliminating the A frequency band when power is supplied may be used.

In the above embodiment, the pay television signal of the B frequency band is converted into the C frequency band adjacent to the upper side of the A frequency band, but when the pay television of the B frequency band is received,
Since the television transmitted from the broadcasting station is not received at the same time, the A frequency band may be converted instead of the C frequency band. In that case, when the power switch 44 is closed, the filter unit 10 largely attenuates frequencies below the audio signal in the A frequency band as shown in FIG. Is greatly attenuated. Therefore, when the television receiver receives a signal obtained by converting the pay television signal in the B frequency band into the A frequency band in the converter unit 4, it is affected by the A frequency band television broadcasting signal from the broadcasting station. There is no such thing.

〔effect〕

As described above, according to the present invention, a pay television signal or the like as it is cannot be received by the television receiver, and at least one television signal receivable by the television receiver as it is. The pay television signal is divided into two by a divider, and the pay television signal is extracted from the one divided output, and the pay television signal is divided into the same frequency band as the above-mentioned at least one receivable television signal or an upper frequency band adjacent thereto. At the time of conversion, the at least one television signal that can be received as it is or the audio signal thereof is greatly attenuated by the filter section to which the other distributed output is supplied. Therefore, when receiving a pay television signal, it is necessary to attenuate the audio signal of at least one television signal that can be received as it is before being transmitted to the distributor without causing an audio beat failure. Therefore, even when receiving at least one television signal that can be received as it is, it can be received well. Moreover,
The filter section has a characteristic of passing at least one television signal that can be received as it is when power is not supplied, and when the power is supplied, the television signal that can be received as it is or Since the audio signal is attenuated, when a television signal receivable by the television receiver is provided in the distributor in addition to the at least one television signal receivable as it is, of course, Even when power is supplied to the filter unit, by switching the channel of the television receiver, it is possible to improve the television signal that can be received as it is, other than the at least one television signal that can be received as it is. Can be received. Moreover, according to the present invention, power is supplied to the converter section and the filter section only when the television signal of the first frequency band is converted to the second frequency or its upper frequency band, resulting in unnecessary power consumption. It is possible to save energy.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the mixing apparatus according to the present invention, FIG. 2 is a circuit diagram of the filter section of the same embodiment, and FIG. 3 is a diagram when the power of the filter section of the same embodiment is not supplied. FIG. 4 is a frequency characteristic diagram when power is supplied to the filter unit of the embodiment. 4 ... Converter unit, 6 ... Converter unit power supply terminal, 8 ...
Power supply terminals for the mixing section, 10 ... filter section, 36 ... filter section.

Claims (1)

[Scope of utility model registration request] 1. A television signal in a first frequency band that cannot be received by a television receiver and a television signal in a second frequency band that can be received by the television receiver,
A distributor for receiving at least an input and distributing these television signals, and a signal for receiving the signals distributed from this distributor and, when power is supplied to the converter power supply terminal, a television signal of the first frequency band from the distributor. And frequency-converting this into a television signal in the second frequency band or an upper adjacent frequency band thereof, and stopping the frequency conversion operation when the power is not supplied to the power source terminal of the converter section. The converter receives the signals from the distributor and the distributor, and has a frequency characteristic that allows the television signal of at least the second frequency band to pass when power is not supplied to the filter power supply terminal, and power is supplied to the filter power supply terminal. The output of the filter section, the converter section, and the filter section that have different frequency characteristics from those of the above A mixing section for mixing a signal, and a power switch connecting the interconnection point between the converter power supply terminal and the filter unit power supply terminal to an external power source, wherein,
The different frequency characteristic of the filter unit is the frequency characteristic that cuts off the television signal of the second frequency band when the converter unit frequency-converts into the television signal of the second frequency band. When performing frequency conversion into a television signal in the upper adjacent frequency band, the second
The mixing device selected for the frequency characteristic that cuts off the audio signal of the television signal in the frequency band of.