JPH03201618A - Frequency data storing method - Google Patents

Abstract

PURPOSE:To enable correct automatic memory to correspond to the strength of an electric field by attenuating a broadcasting wave for the broadcasting wave with strong electric field strength, executing the automatic memory and continuously storing the prescribed number of broadcasting waves into the idle area of the memory in the state of not executing attenuation when the broadcasting waves are not stored in the memory. CONSTITUTION:A reception unit 1 and a control unit 2 are provided and when the automatic memory operation is executed, at first, the strength of a signal attenuating the broadcasting wave with a first attenuation factor is compared with a reference value. When it is judged that the strength is more than the reference value, the frequency data of the broadcasting wave are stored in a memory 22. When the frequency data stored in the memory 22 does not reach a prescribed number, the strength of the second signal attenuated by the second attenuation factor smaller than the first attenuation factor is compared with the reference value and the frequency data of the broadcasting waves with the electric field strength more than the reference value are successively stored into the memory within a range not to exceed the prescribed number so that the same frequency data can not be stored. Thus, the electric field strength of the broadcasting wave can be correctly compared and the correct automatic memory function is realized.

Description

[Detailed Description of the Invention] [Summary] The present invention has an automatic gain control function, so-called AGC function, sweeps a predetermined frequency band, and transmits frequency data of a predetermined broadcast wave to a broadcast wave with a strong reception field strength. A method for storing frequency data in a receiving device having a so-called automatic memory function, which stores a predetermined number of frequency data sequentially from If the stored number does not reach a predetermined number, the AGC will cancel the attenuation of the broadcast wave or store the frequency data of the broadcast wave in a reduced state.
This operation prevents the signal indicating the received electric field strength from responding to changes in the actual received electric field strength, thereby preventing accurate comparison of the electric field strength of broadcast waves.

[Industrial application field]

The present invention provides a receiving device having a function (hereinafter referred to as auto memory function) of sweeping a predetermined frequency band and storing a predetermined number of frequency data of predetermined broadcast waves in a memory in order of broadcast waves having the strongest received field strength. This invention relates to a frequency data storage method.

[Conventional technology]

Conventionally, by operating the auto memory key, multiple (for example, 6) broadcast waves within the received same wave number band are automatically stored in memory, and the stored frequency data can be selectively read out by operating the pre-seven key. An automatic memory function that performs reception based on frequency data has been put into practical use.

In this auto-memory function, the general method is to sweep the reception frequencies in order from the lowest frequency of the reception frequency band and store the frequency data in the preset memory in the order of the broadcast waves with the strongest electric field strength.

When such an auto-memory operation is performed, the electric field strength of the broadcast wave being received is detected based on the signal level of the general intermediate frequency amplification stage (hereinafter referred to as IF stage) and the detection stage.

[Problem to be solved by the invention]

On the other hand, in a receiver, automatic gain control (AGC) is performed to ensure good reception regardless of the strength of the electric field of broadcast waves. In this type of AGC, the IF stage detects the electric field strength of the broadcast wave, and when the electric field strength is strong, the gain of the high frequency amplification stage (hereinafter referred to as RF stage) is reduced to keep the output signal strength constant. There is.

Therefore, due to the influence of AGC, the No. 13 level of the IF stage and detection stage has a region that is not proportional to the received electric field strength, and when detecting the electric field strength based on that signal level, it becomes impossible to compare the electric field strength correctly. .

The present invention solves these problems.

[Means to solve the problem]

In order to solve the above problems, the present invention includes an automatic gain control function, sweeps a predetermined frequency band, and collects frequency data of receivable broadcast waves by a predetermined number of broadcast waves in order of reception field strength. A method of storing frequency data in a receiving device in which the frequency data is stored in the memory by sweeping the received broadcast wave over the receiving frequency band and storing the received broadcast wave in the first
The intensity of the first signal attenuated by the attenuation rate is compared with the reference value, and when it is determined that the intensity of the first signal is greater than or equal to the reference value by the comparison, the frequency data of the broadcast wave is stored in the memory. If the frequency data stored in the memory by storing over the reception frequency band is less than the predetermined number, the received broadcast wave is attenuated by a second attenuation rate smaller than the first attenuation rate. The intensities of the two signals are compared with the reference value, and the frequency data of the broadcast waves for which the intensity of the second signal is greater than or equal to the reference value is determined within the range where the frequencies stored in the memory do not exceed the predetermined number and are the same frequency. It is characterized in that data is stored sequentially so that it is not stored.

[For production]

When performing auto memory operation, first compare the strength of the first signal obtained by attenuating the broadcast wave at the first attenuation rate with the reference value, and when it is determined that the strength is greater than the reference value, the frequency data of the broadcast wave is stored in the memory. I will remember it.

If the frequency data stored in the memory in this way does not reach a predetermined number, the intensity of the second signal attenuated at a second attenuation rate smaller than the first attenuation rate is compared with the reference value, and the intensity is determined to be greater than or equal to the reference value. Frequency data of broadcast waves having an electric field strength of 1 are sequentially stored in the memory so that the frequency data stored in the memory does not exceed a predetermined number and the same frequency data are not stored.

[Embodiments of the invention]

The present invention will be described in detail below using the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In addition, in this example, the first attenuation rate mentioned above is 40 dB,
Further, OdB, that is, a value at which no attenuation is performed, is adopted as the second attenuation rate.

11 is an RF amplifier that selectively tunes and amplifies the broadcast wave from the antenna 10; 13 is a local oscillator that generates a local oscillator signal with a frequency corresponding to the reception frequency; 12 is a radio frequency (RF) amplifier that combines the signal from the local oscillator 13; A mixer mixes the high frequency signal from 11 and converts the frequency to an intermediate frequency; 14 is an intermediate frequency (IF) that amplifies the intermediate frequency signal from mixer 2;
An amplifier, 15 is a detector that converts the signal from the IF amplifier 14 into an acoustic signal, 16 is a low frequency amplifier that amplifies the acoustic signal from the detector 15 and drives the speaker 17, and 18 is an I
RF amplifier 1 based on the strength of the signal from F amplifier 14.
This is an AGC amplifier that controls a gain of 1. The receiving unit 1 is configured by these configurations.

On the other hand, 21 is a central processing unit (CPU) that controls each part;
22 is a memory provided in connection with the CPU 21 and in which frequency data etc. are preset; 23 is an analog/digital (A/D) that converts the S meter signal (described later) from analog to digital to generate field strength data SL; converter,
24 is a PLL unit that controls the receiving frequency in the receiving unit 1 according to the N value, which is frequency data given from the CPU and 21. The control unit 2 is configured by these configurations.

The control unit 2 also includes a switch M for starting auto memory operation, and preset switches P1 to P6 for selectively reading frequency data preset in the memory 22 and performing reception based on the frequency data. It is provided.

The RF amplifier 11 attenuates the broadcast wave received by the antenna 10 by a predetermined attenuation degree (for example, 40 dB) using the attenuation signal ATT output from the CPU 21, and also adjusts the tuning frequency using the bias signal TB output from the PLL unit 24. controlled to change. Further, the bias signal TB is also given to the local oscillator 13, and the local oscillator signals I and 0 outputted from the local oscillator 13 are given to the PLL unit 24, thereby forming a PLL loop.

The detector 15 also outputs to the control unit 2 a binary signal SD indicating whether or not a broadcast wave exists at the frequency currently being tuned, and a signal S meter indicating the electric field strength of the frequency currently being tuned. ing. In the control unit 2, the signal SD is CP
After the signal S meter is converted into electric field strength data SL by the A/D converter 23,
It is taken into PU21.

The signal S meter is obtained by detecting the intermediate frequency signal given from the IF amplifier 14 to the detector 15, and the signal SD corresponds to the signal S make and the lower limit of the receivable electric field strength. This is obtained by comparing the signal S meter with a reference voltage and determining whether the signal S meter is higher than the reference voltage.

Next, the characteristics of the signal S meter in the receiving unit 1 will be explained. FIG. 2 is a characteristic diagram showing the relationship between received electric field strength and signal S make. Incidentally, in FIG. 2, the solid line indicates the characteristics when the attenuation signal ATT is not output and the RF amplifier 11 is not attenuating the broadcast wave.
The dashed dotted line shows the characteristics in a state where the attenuation signal ATT is output and the RF amplifier 11 is attenuating the broadcast wave. Note that the reception electric field strength of the broadcast wave that can be received by the receiving unit 1 is within the range α, and the difference between the upper and lower limits is about 80 dB.

When the attenuation signal ATT is not output, the signal S meter level increases approximately in proportion to the received electric field strength when the received electric field strength is within the region β, as shown by the solid line, but the received electric field strength increases. is within the region γ, AGC
is in effect and the gain of the RF amplifier 21 is suppressed, so that even if the received electric field strength increases, the level of the signal S meter hardly increases. The range of this region β is typically about 40 dB.

On the other hand, when the attenuated signal ATT is output, the broadcast wave is attenuated by about 40 dB, so when the received electric field strength is within the region T as shown by the - dotted chain line, the signal S meter is proportional to the received electric field strength. It will continue to increase. Furthermore, the attenuation signal ATT
When this occurs, if the received electric field strength is in the region β, reception becomes impossible. Therefore, when the attenuated signal ATT is output, the received field strength of the broadcast wave whose received field strength is in the region γ can be correctly compared, and based on the comparison result, the received frequency data is sent to Memo I), 22. Can be stored in order.

Next, the operation of this embodiment will be explained. FIG. 3 is a flowchart showing the operation of the cpU 21.

When the switch M is operated, the process moves to step S1, where the initial setting, that is, the lower limit value 1 of the reception frequency band is set as the N value, and the memory area A for precent allocated in the memory 22 and the memory area A for work are set. After the data group consisting of the lower limit frequency data and the lowest electric field strength data is stored in the memory area B, the process moves to step S2) and step S3 to output the attenuation signal ATT.

In step S3, in order to sweep the reception frequency from the lower limit to the upper limit of the reception frequency band, the N value given to the PLL unit 7 unit 24 is increased by 1 and outputted to the PL[, 1 unit 24, and the PLL unit 2L'l<Stop processing until the time required for locking has elapsed (step S4)
, and then moves to step S5.

In step S5, it is determined whether there is a receivable broadcast wave based on the signal SD, and if there is a signal SD, the process moves to step S6.
If there is no signal SD, the process moves to step Sll. In addition, in this state, the broadcast wave is attenuated by the attenuation signal ATT, so when the received field strength is in the region β in FIG. 2, the signal SD is not generated, and the broadcast wave with the received field strength in the region γ is received. The signal SD will be generated only when the

In step S6, the signal S meter is converted into electric field strength data sr through the A/D converter 23 and taken in, and the electric field strength data SL is stored in a variable SO (step S6).
7), proceed to step S8. In step S8, it is determined whether or not there is a data group whose electric field strength data is less than or equal to SO among the data groups stored in the memory area A.
If there is such data, the process moves to step S9, where the data group consisting of the N value and the variable SO is stored in the area in memory area A where the data group with the smallest electric field strength data is stored, and then the data group consisting of the N value and the variable SO is stored in the area where the data group with the smallest electric field strength data is stored. A rearrangement (sorting) process is performed based on the electric field strength data, and the process moves to step Sll. Note that the data group in memory area A has been sorted in step SIO, and the data group with the smallest electric field strength data in memory area A is stored at a predetermined position. It is sufficient to compare the electric field strength data of the data group stored at the predetermined position in the variable SO, and step S9
Then, the data group consisting of the current N value and the variable SO may be stored in that predetermined position.

In step Sll, it is determined whether the N value has reached the upper limit of the frequency in the reception frequency band to be swept. If it has not reached it, the process returns to step S3 and steps S3 to Sll are performed.
While repeating the above process, receivable broadcast waves are stored in the memory area A, and if the upper limit of the frequency has been reached, the process moves to step S12.

In step S12, it is determined whether the data group for six broadcast stations has been stored in the memory area A. If it has been stored, the process ends, but if it has not been stored, the attenuation signal ATT is canceled ( Step 513) Step S14
Move to.

In step S14, the N value is updated again, and in step S15
Move to. That is, in step S14, the N value is once set to the lower limit value of the reception frequency band to be swept, and thereafter in step S1
4 increases the N value by 1.

In step S15, it is determined whether or not the current N value has already been stored in memory area A. If it has already been stored, there is no need to store it again, so the process moves to step S23, and if it has not been stored, P L The process is stopped until the time required for the L unit 24 to lock has elapsed (step 516), and then the process moves to step S17.

In step S17, the signal SD indicates the presence or absence of receivable broadcast waves.
If there is a signal SD, the process moves to step 318, and if there is no signal SD, the process moves to step S23.

In step 31B, the signal S meter is converted into electric field strength data SL via the A/D converter 23 and taken in, and the electric field strength data SL is stored in a variable SO (step 51
9), move on to Ste Nob S20. In step S20,
It is determined whether or not there is a data group whose electric field strength data is less than SO in the data group stored in memory area B. If there is such data, the process moves to step S21 and is made up of the N value and the variable SO. The data group is stored in the area in memory area B where the data group with the smallest electric field intensity data is stored, and a sorting process is performed based on the electric field intensity data in memory area B, and the process moves to step S23. . Note that the data group in the memory area B has been sorted in step s22, and the data group with the smallest electric field strength data in the memory area B is stored at a predetermined position. B
It is sufficient to compare the electric field strength data of the data group stored at the predetermined position in the variable SO with the variable SO, and in step S21, the data group consisting of the current N value and the variable SO may be stored at the predetermined position. good.

In step S23, it is determined whether the N value has reached the upper limit of the frequency in the receiving frequency band to be swept. If it has not reached the upper limit, the process returns to step 314 and steps S14 to S
While repeating the process of step S23, receivable broadcast waves are stored in the memory area B, and if the upper limit of the frequency has been reached, the process moves to step S24.

In steps S and 24, the data group stored in the memory area B in steps 314 to S23 is sequentially added to the free area in the memory area A in descending order of electric field strength data, and the process ends.

In this embodiment, first, a data group of receivable broadcast waves is stored in the memory area A by sweeping the reception frequency band with the broadcast wave attenuated, and a predetermined number of data groups are stored in the memory. If so, it will end there.

Further, if a predetermined number of data groups are not stored in memory area A, after canceling the attenuation of the broadcast waves, the reception frequency band is swept again and a data group of receivable broadcast waves is stored in memory area B; The data group stored in memory area B is added to the free area of memory area A.

Therefore, for broadcast waves with strong electric field strength as shown in the region γ in FIG. 2, the signal ATT is used to attenuate the broadcast waves so that the electric field strength data SL is proportional to the electric field strength. Since the operation is performed, it is possible to prevent detection of the electric field strength of the broadcast wave, and it is possible to perform correct auto-memory according to the electric field strength.

Also, when sorting data groups stored in memory, a data group stored in memory area A with broadcast wave attenuation performed and a data group stored in memory area B without broadcast wave attenuation. Since these are sorted separately, there is no need to correct the field strength data SL that has changed due to attenuation of the broadcast wave, and it is possible to prevent the sorting process from becoming complicated.

In this embodiment, 40 dB is used as the first attenuation rate, and OdB is used as the second attenuation rate, but the present invention is not limited to this.

[Effects of the Invention] As described in detail above, according to the present invention, when a broadcast wave has a strong electric field strength, the broadcast wave is attenuated to perform an automatic memory operation, and the broadcast wave is in an attenuated state. When a predetermined number of broadcast waves are not stored in the memory, they are stored in an empty area of the memory without attenuation. Correct auto-memory can be performed accordingly.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a characteristic diagram showing the relationship between received electric field strength and signal S make, and FIG. 3 is a flow chart showing the operation of the CPU 21. In the figure, 1: receiving unit, 2: control unit, 10: antenna, 11: RF amplifier, 12: 5x, 13: local oscillator, 14: IF amplifier, 15: detector, 21? '
CPU, 22: Memory, 23: A/D converter, 24
7 PLL unit.

Claims (1)

[Scope of Claims] A receiving device that has an automatic gain control function, sweeps a predetermined frequency band, and stores a predetermined number of frequency data of receivable broadcast waves in a memory in order of broadcast waves having the strongest received field strength. A frequency data storage method in which the received broadcast waves are swept over the received frequency band and the received broadcast waves are stored in the first
The intensity of the first signal attenuated by the attenuation rate is compared with the reference value, and when it is determined that the intensity of the first signal is greater than or equal to the reference value by the comparison, the frequency data of the broadcast wave is stored in the memory. If the frequency data stored in the memory by storing over the reception frequency band is less than the predetermined number, the received broadcast wave is attenuated by a second attenuation rate smaller than the first attenuation rate. The intensities of the two signals are compared with the reference value, and the frequency data of the broadcast waves for which the intensity of the second signal is greater than or equal to the reference value is determined within the range where the frequencies stored in the memory do not exceed the predetermined number and are the same frequency. A frequency data storage method characterized in that the data is stored sequentially so that the data is not stored.