JPH01196912A - Satellite broadcast receiver - Google Patents

Abstract

PURPOSE:To quicken the arrival of the receiver to normal image reception by varying an oscillated frequency of a local oscillation circuit into a frequency for new channel so as to enable the broadcast of said channel to be received. CONSTITUTION:Plural broadcast signals coming from a converter 3 are mixed with a local oscillation signal and the result is an intermediate frequency signal. Only a prescribed frequency of the intermediate frequency signal passes through a band-pass circuit 11 and demodulated by an FM demodulation circuit 12. A television signal is extracted from the demodulated signal and outputted from an output terminal 7. If any frequency deviation exists in the broadcast signal, the deviation of an AFC signal outputted from the FM demodulation circuit 12 from a prescribed value is discriminated by a discriminated circuit 21 and the frequency of the local oscillation signal is varied by a correction signal given from a correction circuit to the local oscillation circuit 14 corresponding to the result of discrimination. Thus, if any frequency deviation exists in the broadcast signal from the converter 3, the operation that the signal is demodulated normally and the normal television signal is to be outputted is quickened.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention selects a desired channel signal from among a plurality of channel broadcast signals from a satellite broadcast converter, and extracts a television signal from the broadcast signal of the selected channel. More specifically, the satellite broadcasting receiver is equipped with an automatic frequency control circuit to enable normal reception of the signal even if there is a frequency deviation in the signal from the converter. Regarding the receiver.

(Prior art) AF given to automatic frequency control circuit from FM demodulation circuit
There is a system in which the frequency of the local oscillation signal is sequentially changed so that the value of the C signal reaches a predetermined value (see, for example, Japanese Patent Laid-Open No. 61-294938).

[Problem to be solved by the invention]

In this conventional satellite broadcasting receiver, in order to make the value of the AFC signal reach a predetermined value, it is necessary to reduce the step width of the change in the frequency of the local oscillation signal. It takes a large number of repetitions to change the oscillation frequency by 1 step, and if the result is still insufficient for the above normal output, then change the oscillation frequency by 1 step. There was a problem in that it took a long time to become possible.

The present invention has been made in view of the above points, and its purpose is to correctly demodulate the signal and output a normal television signal when there is a frequency deviation in the broadcast signal from the converter. To provide a satellite broadcasting receiver capable of quickly performing operations up to a state where

[Means to solve 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 coming from the converter are mixed with a local oscillation signal to form respective 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. If there is a frequency deviation in the broadcast signal, a determination circuit determines whether the FC signal output from the FM demodulation circuit deviates from a predetermined value, and a correction circuit outputs a signal to the local oscillation circuit in accordance with the determination result. The frequency of the local oscillation signal is changed by the corrected signal. The result appears as a change in the AFC signal. The above operation is repeated while changing the correction signal sequentially.

When the change in the AFC signal exceeds a predetermined value, a stop signal is generated from the stop signal generating means.
Changes in the correction signal are stopped, and changes in the frequency of the local oscillation signal are stopped.

〔Example〕

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

In FIG. 1, 1 indicates a satellite broadcast receiver. In this, 2 is an input terminal to which a satellite broadcast converter 3 can be connected. The above converter 3 is provided for a receiving antenna 4 for satellite broadcasting.

As is well known, the receiving antenna 4 includes a reflector 5 and a primary radiator 6.
Consists of. Next, 7 is an output terminal to which a well-known television receiver 8 can be connected.
For example, 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 band. The circuit 11 may be a bandpass filter. 12 is an FM'4jLm circuit which performs FM demodulation of the signal output from the circuit 11 and outputs a demodulated signal and an AFC signal.
As shown in the attached graph, the signal is a signal whose voltage value changes depending on the deviation of the frequency of the signal coming through the bandpass circuit 11 from the normal frequency, and generally has an S curve. It's called a signal. Reference numeral 13 denotes a television signal extraction circuit, which extracts a television signal from the demodulated signal.

Reference numeral 14 denotes a local oscillation circuit which oscillates a local oscillation signal having a frequency corresponding to the control signal inputted to the control input terminal 14a and supplies it to the mixer 10 from the output terminal 14b. 16 is a reference signal supply means which selects a plurality of reference signals for setting the oscillation frequency of the local oscillation circuit 14 to a frequency corresponding to each of the plurality of channels input from the satellite broadcast converter 3 to the input @2. It is now possible to output it visually.

Reference numeral 17 denotes an operating member attached to the reference signal supplying means 16, which is a keypad having a power key for turning on and off the power and a channel selection key for selecting the reference signal.

Next, 20 is an automatic frequency control circuit connected between the FM demodulation circuit 12 and the local oscillation circuit 14.
This is for inputting an FC signal and providing a signal to the local oscillation circuit for correcting the oscillation frequency of the local oscillation circuit in response to the deviation of the AFC signal from a predetermined value, and is configured as follows. Reference numeral 21 denotes a discrimination circuit, which discriminates whether the AFC signal input to the input terminal 21a is high or low from a predetermined value, for example, as shown in the attached graph, from the reference voltage, and issues a descending command, for example, L, in response to the magnitude. A logic signal or a command signal such as a rise command, for example a logic signal of H, is outputted from the output terminal 21b. 22 is a correction means that receives a command signal from the discrimination circuit at an elevation control terminal 22a (also called a command signal input terminal), and sequentially adjusts the oscillation frequency of the local oscillation circuit 14 in response to the descending command or ascending command, respectively. A correction signal that changes in a stepwise manner to decrease or increase is outputted from the output end 22b. The correction means 22 also has a stop control terminal 22C (also called a stop signal input terminal), and by receiving a stop signal there, the rise or fall of the correction signal is stopped. Reference numeral 23 denotes a stop signal generating means, which receives a command signal from the discrimination circuit 21 at an input end 23a, and outputs a stop signal from an output end 23b when the command signal changes from -down command to up command or vice versa. It is.

Next, the operation of the above configuration will be explained. 2 (81,
(As shown in bl, 11 channels of broadcast signals and 1
5 channel broadcast signals are received.

Their frequency is the regular frequency dissipation 1241.28MH
For example, 1 and 5 M upwards from z and 1318 MHz, respectively.
Hz deviation (this deviation is unique to the converter 3 and has already occurred when the converter 3 is adjusted by the manufacturer so that it falls within the predetermined standard, The deviation is generally within ±2 MHz of the normal frequency), and in the above state, when the power key on the operating member 17 is operated to turn on the power to the receiver 1ml, the reference signal supply means 16 outputs the signal that has not been set in advance. A reference signal corresponding to a certain channel, for example channel 11, is output. The signal is local oscillator circuit 1
4, and the circuit 14 oscillates a local oscillation signal of 1644.06 MHz, which is applied to the mixer 10, as shown in the enlarged view on the right side of FIG. Then, the above input signal is converted into an intermediate frequency signal of 401°28MHz for the 11th channel signal and outputted from the mixer 1o, and for the 15th channel signal is converted to a 401°28MHz intermediate frequency signal and outputted from the mixer 1o.
It is converted into a 4.56MHz intermediate frequency signal and sent to mixer 10.
is output from. Of these intermediate frequency signals, only the intermediate frequency signals of 11 channels can pass through the band pass circuit 11 having a pass band indicated by reference numeral 25, and are applied to the FM demodulation circuit 12. The FMi adjustment circuit 12 adjusts the frequency of the above-mentioned incoming intermediate frequency signal to a normal intermediate frequency of 402.78.
Since the deviation is smaller than MHz, an AFC signal with a smaller voltage is output in accordance with the deviation.

Upon receiving the AFC signal, the discrimination circuit 21 determines that the AFC signal has a predetermined value (the voltage value of the AFC signal when the frequency of the intermediate frequency signal input to the FM demodulation circuit 12 is the regular intermediate frequency of 402.78 MHz). It determines that it is smaller than , and outputs a rising command signal, that is, an H signal. Receiving this rising command signal, the correction means 22 adjusts the local oscillation circuit 1.
For example, I
Outputs a correction signal to increase the frequency by MHz. Then, the oscillation frequency of the local oscillation circuit 14 becomes 1645.06 MHz as shown in the enlarged view of FIG.
The intermediate frequency of one channel is 402.28 MHz, and since this frequency is within the band in which normal demodulation can be performed by the FM demodulation circuit 12, as shown by reference numeral 26, the demodulated signal output from this demodulation circuit A television signal is extracted from the television signal extraction circuit I3, and is provided to the receiver 8 via the output terminal 7. As a result, normal video and audio can be obtained on the receiver 8.

When the intermediate frequency signal has the above value, the AFC signal output from the FM repeater circuit 12 is still smaller than the reference voltage, so the discrimination circuit 21 continues to output the rising command signal. Therefore, the correction signal outputted from the correction means 22 changes into a signal that further increases the oscillation frequency of the local oscillation circuit 14 by IM)Iz. As a result, the oscillation frequency of the local oscillation circuit 14 changes to 1646.06 MHz, and the frequency of the intermediate frequency signal changes to 403.288H2. Since this frequency is still within the range 26, the television signal can be outputted to the television receiver 8 without any problem. A
As is clear from the graph of FIG. 1, the FC signal becomes larger than the reference voltage, so the discrimination circuit 21 discriminates this, and its output changes from a rise command signal to a fall command signal. This change is detected by the stop signal generating means 23, which outputs a stop signal to the correcting means 22. Then, the correction signal output from the correction means 22 stops changing thereafter. As a result, the frequency of the local oscillation signal output from the local oscillation circuit 14 is fixed at 403.28 MHz. Therefore, normal output of the television signal to the television receiver 8 is continued.

Next, when the channel selection key on the operating member 17 is operated in order to receive channel 15, the reference signal supply means 16 outputs a reference signal corresponding to channel 15. Then, the local oscillation circuit 14 becomes 1 as shown in FIG.
Outputs a local oscillation signal of 720.78MHz. By inputting this signal to the mixer 10, the 11th channel becomes 478MH2, and the 15th channel becomes 401.28MHz.
Each signal is converted to Hz and output from mixer 1o.

After that, the operation is completely the same as when receiving the 11 channels mentioned above, and the oscillation frequency of the local oscillation signal generator 4 is 172.
The frequency changes in stages from 1.78 MHz to 1722.78 MHz. And the frequency of the intermediate frequency signal is 403°2
It is fixed at 8MHz. Also, in this process, a normal television signal is output from the output #i7 to the television receiver 8.

Next, FIG. 3 is a block diagram showing an example of the above local oscillation ti21Il\814, where 31 is a reference oscillator, 32 is a phase comparator, 33 is a loop filter, 34 is a VCo, 35 is a prescaler, and 3G is a programmable divider. show.

In such a circuit, the signal from the reference oscillator 31 and the signal oscillated by the VCO 34 and passed through the prescaler 35 and the divider 36 are compared in the phase comparator 32, and the VCO 34 is controlled by the output signal. .

Further, the programmable divider 36 is connected to the input terminal 14a.
The frequency division ratio is set according to the control signal applied to the frequency division ratio. Therefore, the local oscillation signal output from the VCO 34 has a frequency corresponding to the control signal.

Next, FIG. 4 shows the reference signal supply means 16 and the operating member 17.
This shows an example of the configuration, where 38 is a memory and 39 is a switch.
When the power key 17a is operated, the switch 39 closes, and the reference signal stored in the memory 38 in advance is applied to the switch 3.
It is output through 9. Further, the reference signal outputted from the memory 38 is changed by operating the channel selection key 17b, and is outputted through the switch 39.

Next, FIG. 5 is a block diagram showing an example of the discrimination circuit 21.
Reference numeral 41 indicates a reference voltage generation circuit, and reference numeral 42 indicates a voltage comparison circuit. In such a structure, a signal entering the input terminal 21a is converted into a reference voltage from the reference voltage generation circuit 41 in the voltage comparison circuit 42. When the input signal is lower than the reference voltage, an H signal is output, and when it is higher, an L signal is output from the output terminal 21b.

Next, FIG. 6 is a block circuit diagram showing an example of the correction means 22, which is composed of a correction command circuit 44 and a correction change command circuit 45. In the correction command circuit 44, 46.47 indicates an above down counter, 468.47a is a data end, 46b,
47b is the output terminal, 46c is the amplifier down control input terminal, 4
6d indicates a clock end, 46'e indicates a load end, and each counter 46.47 is an IC 74LS191.
The zero-order correction change command circuit 45 is used to supply a signal to the correction command circuit 44 to command a change in correction, and 48 is a pulse generation circuit that generates a pulse signal at predetermined time intervals. .

49 is a switch, and 50 is a counter circuit that counts the number of pulses output from the pulse generating circuit 48 and is reset by a signal from a reset circuit 51. Note that 22d indicates a reference signal input terminal, and the signal from the reference signal supply means 16 is input to the input terminal 22d,
The signal can be applied to the local oscillation circuit 14 through the correction command circuit 44 and the output terminal 22b.

In the configuration described above, when the power key or the channel selection key on the operating member 17 is operated, the reset circuit 51
The counter circuit 50 is reset. In this state, the reference signal that enters the input end 22d becomes a control signal as it is, and is output from the output end 22b. The switch 49 is turned on by operating the above operating member. As a result, the pulse generated by the pulse generating circuit 48 is transmitted to the switch 4.
9 and is input to the clock terminal 46d. counter 4
6.47 functions as a down counter when the signal input to the up/down control input terminal 46C is at H level, and functions as an up counter when it is at L level, and each time a pulse is input to the clock terminal 46d, the above A correction signal is added to increase or decrease the oscillation frequency of the local oscillation circuit with respect to the reference signal by increasing or decreasing the high-order digit part of the digital data of the reference signal. The added signal is output from the output end 22b. The pulse output interval from the pulse generating circuit 48 is determined as follows.

That is, the reference signal is corrected to change the oscillation frequency of the local oscillation circuit, and as a result, the frequency of the intermediate frequency signal changes, and the AFC signal changes, and the time it takes for it to reach the discrimination circuit 21 and produce the result. (for example, 0.08-seconds) or more is set to, for example, 0.1 seconds. When a stop signal is input to the stop signal input terminal 22c during the operation in which the correction is applied as described above, the switch 49 is turned off, and the output from the pulse generation circuit 48 is no longer given to the counter 46, so that the correction signal is Changes stop.

The counter circuit 50 counts the number of pulses output from the pulse generating circuit 48, and when the number of pulses exceeds a predetermined number, it turns off the switch 49 and resets the counter 46 to return the correction signal to its initial value. The state is returned to such that the reference signal is directly output from the output terminal 46b as a control signal.

Next, FIG. 7 is a block diagram showing an example of stop signal generating means, in which 52 is a delay circuit and 53 is an exclusive OR circuit. In such a circuit, when the signal applied to the input terminal 23a changes from H to L or from low to H, the output terminal 23b
A pulse signal having a time width equal to the delay time of the delay circuit 52 is output from the time of the above change.

Next, FIG. 8 shows a different embodiment of the present application, and shows an example in which the reference signal supply means, correction means and stop signal generation means are constructed using a microprocessor 55.

In the figure, 56 is an input/output board, 57 is a CPU, and 58
59 represents a ROM, and 59 represents a RAM.

A flow chart of the program executed by the microprocessor 55 is shown in FIG. 9.10. When the power is turned on by pressing the power key, the program starts (step P1), the program progresses from P1 to P2, and at P3, a reference signal is given to the local oscillation circuit. The program then moves to the AFC subroutine of P4. AF
After passing through the C subroutine, the program proceeds to steps P5~
The process proceeds to P6. If there is no channel change, step P6 is repeated; if there is, the process returns to P3.

AFC subroutine (2) is executed as follows.

In step P7, the maximum number of repetitions for changing the correction signal is set, for example, 6. Next, the command signal is read in step P9 via P8. Next, through PIO, when the command signal is a rising command signal at pH, an upward correction is performed at Pl2, and when it is a falling command signal, a downward correction is performed at Pl3.
A control signal with a correction command added is given to the local oscillator circuit.The program proceeds to Pl5, and then Pl5.
Repeat steps 8 to P15, and in the process P
When IO becomes NO, a stop signal is output at Pl6, and A
The FC subroutine ends. When P8 becomes YES, the original reference signal is applied to the local oscillation circuit at Pl7, and the AFC subroutine ends.

Next, FIG. 11 showing a different embodiment of the present application will be described. A small correction means 61 outputs a correction signal for changing the frequency of the local oscillation signal in steps of, for example, 192 KHz. 62 is a minute correction means, for example 6
It outputs a correction signal that changes the frequency of the local oscillation signal in steps of 4KHz.

In these, 61a to 61c and 62a to 62c indicate terminals similar to terminals 22a to 22c in the correction means 22.

The configuration shown in FIG. 11 above is replaced by the microprocessor 55 shown in FIG.
When the program is executed by the microprocessor 55, the program executed by the microprocessor 55 is shown in a flowchart.
~14 and Figure 10. It should be noted that parts that are functionally the same or equivalent to those in FIG. 9 are given the same reference numerals as in FIG. 9, and redundant explanations will be omitted.

After executing AFC subroutine ■ in step P4,
AFC subroutine (2) in step P18 is executed. This subroutine ■ is performed at steps P20 to P30 in FIG.
As is clear from the above, the steps are exactly the same as those of the AFC subroutine (2).

When the AFC subroutine (2) in step P18 is completed, the AFC subroutine (2) in step P19 is executed. This subroutine ■ also includes steps P31 to P31 in FIG.
As is clear from 41, the steps are completely equivalent to those of the AFC subroutine.

As a result of the frequency of the local oscillation signal being changed by executing the above AFC subroutines ① to ②, the frequency of the intermediate frequency signal changes sequentially as shown in FIG. 15, and a better reception condition of the television signal is achieved. That is, first, when the local oscillation signal has a frequency corresponding to the reference signal, the intermediate frequency signal becomes f
1, the above intermediate frequency signal becomes f2. It changes to f3. In the process, when the signal changes from fl to f2, a normal reception condition is achieved as described above, and a normal TV signal is output.The primary AFC subroutine■
is executed, the intermediate frequency signal becomes f4. f5゜f
It changes to 6. As a result, a better reception condition (receipt M with less N sound and distortion) is achieved.

Next, when AFC subroutine (2) is executed, the intermediate frequency signal is changed to f7. It changes to f8. As a result, even better reception conditions are achieved.

〔Effect of the invention〕

As described above, in the present invention, when it is desired to change the state in which broadcasting of a certain channel is being received to another channel, the oscillation frequency of the local oscillation circuit 14 is changed to the frequency for the new channel by operating the operating member 17. By changing to , it is possible to output the television signal of that new channel, which has the advantage of making it possible to receive broadcasts of that channel.

Furthermore, even if the frequency of the broadcast signal of the new channel from the converter 3 deviates from the regular frequency when the above operation is performed, the oscillation frequency of the local oscillation circuit 14 is sequentially changed according to the deviation. This feature has the advantage that the TV signal of the new channel can be output normally.

Moreover, when the oscillation frequency of the local oscillation circuit 14 is successively changed so as to achieve a normal output state as described above, the AFC signal changes from a value larger than a predetermined value to a value smaller than the predetermined value, or vice versa. Since the change in the oscillation frequency is detected and the change in the oscillation frequency is stopped, the step width of the change in the oscillation frequency is made coarse within the range of 1/2 of the bandwidth that allows normal demodulation by the FM demodulation circuit 12. It has the advantage that the above-mentioned television signal can be output normally even if This means that the number of repetitions of changing the oscillation frequency by one step and, if the result is still insufficient for the normal output, changing the oscillation frequency by another step, can be reduced. This has the effect of quickly reaching a state where normal image reception is possible.

Furthermore, the stop signal generation means 23 consisting of the delay circuit 52 and the exclusive OR circuit 53 and the discrimination circuit 21 consisting of the reference voltage generation circuit 41 and the voltage comparison circuit 42 have a simple configuration, which has the effect of reducing manufacturing costs. .

Furthermore, if there is a counter circuit 50, the stop signal generating means 23
It is possible to prevent the user from selecting an adjacent channel when the channel is out of order.

Furthermore, if the small correction means 61 and the minute correction means 62 are provided in addition to the correction means 22, it is possible to obtain a higher quality television signal with sparkly noise removed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a block circuit diagram, FIG. 2 is a graph for explaining operation, FIG. 3 is a block diagram of a local oscillation circuit, and FIG. 4 is a reference signal supply means and operation. A block diagram of the components, Figure 5 is a block diagram of the discrimination circuit, and Figure 6 is a block diagram of the discrimination circuit.
Figure 7 is a block diagram of the correction means, Figure 7 is a block diagram of the stop signal generation means, Figure 8 is a partial diagram showing an embodiment using a microprocessor, Figure 9 is a flowchart of the main routine, and Figure 10 is the AFC. 11 is a block diagram (partial diagram) showing a different embodiment; FIG. 12 is a flowchart of the main routine of a different embodiment; FIGS. 13 and 14 are flowcharts of AFC subroutines FIG. 15 is a graph explaining changes in the intermediate frequency signal in the example of FIG. 12. 2...Input end, 7...Output end, lO...Mixer,
12...FM demodulation circuit, 14...Local oscillation circuit, 1
6... Reference signal supply means, 17... Operating means, 21
. . . Discrimination circuit, 22 . . . Correction means, 23 . . . Stop signal generation means. Fig. 3 Fig. 4 Fig. 5 Fig. 7 Fig. 6 Fig. 8 Fig. 9-Fig. 1o Fig. 11

Claims (1)

[Claims] 1. An input end for inputting each broadcast signal of a plurality of channels from a satellite broadcast converter, an output end for outputting a television signal to a television receiver, and a cascade between them. A connected mixer, a bandpass circuit, an FM demodulation circuit, a television signal extraction circuit, a local oscillation circuit that provides a local oscillation signal to the mixer, and a local oscillation circuit that changes the frequency of the local oscillation signal to a frequency corresponding to each of the plurality of channels. a reference signal supply means for selectively outputting a plurality of reference signals to be set and providing the same to the local oscillation circuit; an operating member for selectively operating the reference signal; and an automatic frequency control circuit for providing the local oscillation circuit with a signal that corrects the oscillation frequency of the local oscillation circuit in response to the deviation of the AFC signal from a predetermined value. The control circuit is the above A
A discrimination circuit that discriminates the magnitude of the FC signal from a predetermined value and outputs a command signal of a descending command or an ascending command in accordance with the magnitude; A stop signal generating means generates a stop signal when the change is reversed, and a command signal is received from the discrimination circuit, and the local oscillation circuit is configured to gradually lower or lower the oscillation frequency in response to the lower or higher command. a correction means that applies a correction that changes sequentially so as to raise the local oscillation circuit, and that stops changing the correction given to the local oscillation circuit by accepting a stop signal from the stop signal generation means. Broadcast receiver. 2. The satellite according to claim 1, wherein the stop signal generating means comprises a delay circuit whose input signal is the command signal from the discrimination circuit, and an exclusive OR circuit whose input signals are the command signal and the output signal of the delay circuit. Broadcast receiver. 3. The satellite broadcast receiver according to claim 1, wherein the correction applied to the local oscillation circuit by the correction means is a correction that lowers or increases the oscillation frequency of the local oscillation circuit in steps of 1 MHz. 4. The discrimination circuit inputs the reference voltage generation circuit, the AFC signal and the reference voltage, and outputs a discrimination signal of a descending command or an ascending command in response to the higher or lower voltage of the former relative to the latter, respectively. A satellite broadcasting receiver according to claim 1, comprising: 5. A correction change command circuit in which the correction means outputs a signal instructing to change the correction at predetermined time intervals, and stops outputting the command signal after receiving the stop signal, and the above-mentioned raising or lowering command signal. The oscillation frequency of the local oscillator circuit is increased step by step at predetermined intervals in response to a rising or falling command signal each time a signal commanding a correction change is input. 2. The satellite broadcasting receiver according to claim 1, further comprising a correction command circuit that applies correction to the local oscillation circuit that changes sequentially so as to increase or decrease the local oscillation circuit. 6. The satellite broadcasting receiver according to claim 5, further comprising a counter circuit that returns the correction signal to an initial value when the number of correction change commands reaches a predetermined number. 7. After the correction change by the correction means has stopped, a command signal is received from the discrimination circuit, and in response to the descending command or rise command, the oscillation frequency is transmitted to the local oscillation circuit, and the change due to the correction by the correction means is transmitted to the local oscillation circuit. In addition to applying a correction that changes sequentially so as to lower or increase stepwise in a width smaller than the width, the change in the correction given to the local oscillation circuit is stopped by accepting a stop signal from the stop signal generating means. The satellite broadcasting receiver according to claim 1, further comprising small correction means. 8. After the correction change by the small correction means has stopped, a command signal is received from the discrimination circuit, and in response to the descending command or rising command, the oscillation frequency is changed to the local oscillation circuit according to the correction by the small correction means. Adding a correction that changes sequentially so as to decrease or increase in steps with a width smaller than the width of the change, and stop the change in the correction applied to the local oscillation circuit by receiving a stop signal from the stop signal generating means. 8. The satellite broadcasting receiver according to claim 7, further comprising minute correction means.