JPH0227890A - Satellite broadcast receiver - Google Patents

Abstract

PURPOSE:To restore a reception state before power interruption even if the power is interrupted and then restored by providing a storage effectiveness confirming means comprising an oscillated frequency control circuit comprising volatile storage means. CONSTITUTION:A control signal generating means 21 consists of a key code storage section, a channel storage section and a frequency data storage section and is made or RAMs. An uninterruptible power supply circuit 27 is made up of a large capacitance of capacitor or a battery and supplies power to the control signal generating means 21 in the event of power failure. If the power is interrupted and restored again in a short period, a voltage detection circuit 32 detects it, and a comparator circuit 33 compares the storage content of a key code storage ROM 31 with the storage content of the key code storage section in the control signal generating means 21. Since the key code storage section stores the key code, the storage content of each storage section is discriminated to be all correct and the comparator circuit 33 gives a present status output command signal to the control signal generating means 21. Thus, the state before the power is interrupted is restored as it is.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a satellite that selects and receives a signal of a desired channel from among broadcast signals of a plurality of channels from a converter for satellite broadcast reception. Regarding broadcast receivers.

[Conventional technology]

There are some devices in which the oscillation frequency control circuit is configured using volatile storage means.

[Problem to be solved by the invention]

In such devices, there is a problem that when the power is cut off, the contents stored in the storage means are erased, and even if the power is restored afterwards, it is not possible to restore the reception state before the power was cut off. .

The present invention has been made in view of the above points, and its purpose is to enable, even when the power is interrupted and then restored, to restore the reception state before the interruption of the power. To provide satellite receivers.

(Means for Solving the Problems) In order to achieve the above object, the present invention takes the measures as described in the claims above, and its effects are as follows.

[Effect]

A plurality of broadcast signals entering the input terminal are applied to a mixer. Further, by applying a control signal from the oscillation frequency control circuit to the local oscillation circuit, the oscillation circuit outputs a local oscillation signal and provides it to the mixer. In the mixer, the broadcast signal is mixed with the local oscillation signal to form intermediate frequency signals.

Of these intermediate frequency signals, only those of a predetermined frequency pass through the band pass circuit and are demodulated by the FM demodulation circuit.

A television signal is extracted from the demodulated signal and output from the output end.

〔Example〕

The drawings showing the embodiments of the present application will be described below.

In FIG. 1, 1 indicates a satellite broadcast receiver, in which 2 is an input terminal to which a satellite broadcast converter 3 can be connected. The converter 3 is provided for a receiving antenna 4 for satellite broadcasting. Reference numeral 5 denotes an output terminal, which includes, for example, a video signal output terminal 5a and an audio signal output terminal 5b, to which a well-known VTR 6 can be connected.

6a is a power plug of the VTR, and 7 is a television receiver connected to the VTR. Furthermore, the above output terminal 5 is connected to a television receiver 7.
W directly! You may continue.

Next, in the circuit configuration of the satellite broadcasting receiver 1, reference numerals 10 to
Reference numeral 14 shows examples of well-known members, 10 is a mixer, and 11 is an intermediate frequency amplifier exemplified as a band pass circuit, which amplifies and passes only signals in a predetermined frequency band. The circuit 11 may be a bandpass filter, and 12 is an FM demodulation circuit which performs FM demodulation on the signal output from the circuit 11 and outputs a demodulated signal and an AFC signal. Reference numeral 13 denotes a television signal extraction circuit, which extracts a television video signal and audio signal from the demodulated signal. Reference numeral 14 denotes a local oscillation circuit which oscillates a local oscillation signal having a frequency corresponding to an oscillation frequency control signal inputted to a control input terminal 14a and supplies it to the mixer 10 from an output #14b. Next, 15 is an oscillation frequency control circuit, and 16 is a power plug, which is connected to, for example, an outlet of the VTR 6.

Next, the above oscillation frequency mm times j! 115 will be explained.

Reference numeral 21 denotes a control signal forming means, which is configured to form an oscillation frequency control signal and output it. This forming means 21 has a key code storage section, a channel storage section, a frequency data storage section, and a frequency correction data storage section. Such a forming means is constructed using, for example, a RAM which is a volatile storage element. Reference numeral 22 denotes an initial data storage means, which is constructed using a ROM which is an inadvertent storage element, and stores data as shown in Table 1 below.

Table 1 24 is a channel selection switch connected to the storage means 23.

Reference numeral 25 denotes frequency correction command means, which is designed to generate output signals as shown in Table 3 below depending on the state of the human input signal.

3rd Table 23 shows channel data storage means, the storage means 22
It is constructed using something similar to , and stores data as shown in Table 2 below.

The second table 26 is a display connected to the control signal forming means 21, which obtains data from the channel storage section of the means 21 and displays the channel being received.

Reference numeral 27 denotes an uninterruptible power supply circuit, which is constructed with a large capacity capacitor or battery, and is adapted to supply power to the control signal forming means 21 during a power outage.

Next, 30 is a transfer control circuit, which is composed of members indicated by numerals 31 to 33. 31 is a key code storage means;
It is constructed using ROM, which is a non-volatile storage element, and can store any key code such as ABCDB as shown in FIG.
Memorize the key code.

Reference numeral 32 denotes a voltage detection circuit which detects voltage applied from the power plug 16 and outputs a detection signal. Reference numeral 33 denotes a comparison circuit which compares the stored contents of the key code storage unit in the control signal forming means 21 and the key code storage means 31, and outputs a transfer command signal or a current output command signal as described later depending on the state thereof. It is.

Next, the operation of the satellite broadcasting receiver 1 will be explained according to a flowchart for explaining the operation in FIG.

In FIG. 2, (A) is a flowchart showing changes in the storage contents of each storage section in the control signal forming means 21.
Inside each frame, the storage contents of the key code storage section, channel storage section, frequency data storage section, and frequency correction data storage section are shown in order from the top, and CB) in FIG. 2 shows the operation of the transfer control circuit 30. In each box, the storage contents of the key code storage means 31, the storage contents of the key code storage section in the control signal forming means 21, and the output of the comparison circuit 33 are shown in order from the top, and (A) and (B) )
Dashed arrows indicate mutually corresponding time points.

First, in the state (a) when the power is not turned on, the control signal forming means 2
All of the storage units in No. 1 are in a state where there is no stored content.

Next, when the power of the receiver 1 is turned on, such as by turning on the power of the VTR 6, power is supplied to each circuit element and the circuit elements are operated. Further, the output signal of the voltage detection circuit 32 is given to a comparison circuit 33, and the comparison circuit 33 compares the storage contents of the key code storage means 31 and the storage contents of the key code storage section in the control signal forming means 21.

In this case, since there is no stored content in the key code storage section of the control signal forming means 21, the comparison circuit 33 provides a transfer command signal to the key code storage means 31 and the initial data storage means 22. As a result, as shown in (b), the key code is given from the key code storage means 31 to the key code storage section in the control signal forming means 21, and the initial channel and initial Frequency data is provided to a channel storage section and a frequency data storage section in the control signal forming means 21, respectively. When the above data is given, the control signal forming means 21 forms an oscillation frequency control signal corresponding to the given frequency data and outputs it to the local oscillation circuit 14.
4 receives the oscillation frequency control signal and outputs a local oscillation signal of a frequency corresponding to the oscillation frequency control signal to the mixer.

On the other hand, the received signals (11.7 to 12.0 GHz) of many channels received by the receiving antenna 4 are sent to the converter 3.
The respective frequencies are converted into first intermediate frequency signals, which are applied to the input terminal 2 of the receiver l. The signal passes from input terminal 2 to mixer IO.

The mixer 10 mixes the first intermediate frequency signal and the local oscillation signal, converts the frequency of the former, and outputs it to the intermediate frequency amplifier 11. The intermediate frequency amplifier 11 passes only signals of a predetermined frequency (second intermediate frequency) among the multiple channels of signals coming from the mixer 10.
In this case, the B5-15 channel is applicable. The output signal of the intermediate frequency amplifier 11 is demodulated by the FM demodulation circuit 12, and the demodulated signal is given to the television signal extraction circuit 13.
There, a video signal and an audio signal are extracted. Each extracted signal is given to, for example, a VTR 6 from each output terminal.

Therefore, the VTR 6 can record the video, and if the TV receiver 7 is connected, the video and audio can be obtained from the TV receiver 7.

On the other hand, among the output signals from the FM demodulation circuit 12, AF
The C signal is given to the frequency correction command means 25 of the oscillation frequency control circuit 15. In this case, the converter 3
When the frequency of the output signal is the same as the predetermined frequency, the level of the AFC signal becomes the same as the predetermined reference level in the frequency correction command means 25, so the command means 25 maintains the frequency. The command data is given to the control signal forming means 21. As a result, the forming means 21 outputs the oscillation frequency control signal as described above.

On the other hand, if there is a frequency deviation in the converter 3, for example, if the frequency of its output signal deviates higher than a predetermined frequency, the frequency of the signal after frequency conversion by the mixer 10 will shift to a lower frequency. As a result, the above AFC
The signal will be lower than the reference level. Then, the frequency correction command means 25 outputs frequency increase correction data (for example, 1001
data) is output as an output signal. This data is given to the frequency correction data storage section in the 11 control signal forming means 21. Then, the control signal forming means 21 forms an oscillation frequency control signal having a frequency value obtained by adding the frequency value of the data in the frequency data storage section to the frequency value of the data in the frequency correction data storage section, and outputs it.

As a result, the oscillation frequency of the local oscillation circuit 14 is corrected,
The frequency of the second intermediate frequency signal of the BS-15 channel output from the mixer 10 deviates less from a predetermined value. Note that if the deviation still exists and the AFC signal is still lower than the reference level, the above operation is repeated. When the AFC signal eventually becomes the same as the reference level, the frequency correction command means 25 supplies frequency holding command data to the 1xny signal forming means 21. Therefore, the control signal forming means 21 maintains the oscillation frequency I11 at that time.
Continue outputting the control signal. Control signal forming means 2 at this time
An example of the stored data of No. 1 is shown in FIG. 2 (c). In this state, the FM demodulation circuit 12 performs a good demodulation action, and high quality video and audio signals are output from the output terminal.

Next, use the channel selection switch 24 to select the receiving channel, for example, B.
5-11, channel data storage means 2
3 to the B5-11 channel and the corresponding frequency data are given to the control signal forming means 21,
The data in the storage section in the control signal forming means 21 is (d)
(can be rewritten. As a result, the control signal forming means 2
The oscillation frequency control signal output from 1 also has a corresponding value. As a result, the oscillation frequency of the local oscillation circuit 14 also becomes a value corresponding to that value, and the signal output from the intermediate frequency amplifier 11 after frequency conversion by the mixer IO becomes B5-1.
There will be only one signal. In this case, column 11 signal forming means 2
Since the oscillation frequency l control signal outputted from the oscillation frequency l control signal has already been taken into account the correction data from the frequency correction data storage section, the signal of B5-11 is properly received from the beginning.

Next, when the power is turned off, each circuit stops its operation, and the output signal from the output terminal 5 disappears. In this case, power continues to be supplied from the uninterruptible power supply circuit 27 to the control signal forming means 21, and the storage contents (d) of each storage section in the control signal forming means 21 are maintained as they are.

Next, when the power is turned on again within a short period of time (while the uninterruptible power supply circuit 27 continues to function), the voltage detection circuit 32 detects this and provides an output signal to the comparison circuit 33. The comparison circuit 33 is connected to the key code storage means 31 as in the above case.
The stored contents of the key code storage section in the control signal forming means 21 are compared. In this case, since the key code is still stored in the key code storage unit,
It is determined that all the stored contents of each storage section of the control signal forming means 21 are correct, and the comparison circuit 33 provides the current output command signal to the control signal forming means 21. As a result, the control signal forming means 21 forms an oscillation frequency control signal based on the data (e) stored in itself, and transmits it to the local oscillation circuit 14.
give to S, the state before the power was turned off is restored as it is, and the broadcast of B5-11 is properly received.

Next, after a long period of time has passed after the power is turned off, the uninterruptible power supply circuit 27 stops functioning, and the control signal forming means 2
The storage contents of each storage unit in 1 are as shown in (to) (all disappear.

If you turn on the power again in this state, (w) in Figure 2 will appear.
, (G), and (H), the same operations as in the cases (S), (B), and (C) above are performed, and a state is reached in which BS-15 is properly received.

〔Effect of the invention〕

As described above, the present invention has the advantage that satellite broadcasting of a desired channel can be received satisfactorily.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a block circuit diagram of a satellite broadcasting receiver, and FIG. 2 is a flowchart for explaining the operation. 2...Input terminal, 3...Converter, 5...Output terminal, 10...Mixer, 11...Intermediate frequency amplifier, 1
2...FM demodulation circuit, 14...Local oscillation circuit.

Claims (1)

[Claims] an input terminal, an output terminal, a mixer, a bandpass circuit, an FM demodulation circuit, and a television signal extraction circuit connected in cascade between them, a local oscillation circuit that provides a local oscillation signal to the mixer, and the local oscillation circuit. A satellite broadcasting receiver comprising an oscillation frequency control circuit that provides an oscillation frequency control signal to the circuit.