JPS6148225A - Automatic preset system of electronic tuning type radio receiver - Google Patents

Abstract

PURPOSE:To reduce the automatic preset time by replacing a high level into a low level and storing the result to a memory when a reception level of a frequency is higher than the level after storage of a preset memory while a search stop signal is generated during sweeping of a reception frequency. CONSTITUTION:A microcomputer system 3 searches automatically a broadcast frequency by the operation of a start key PRE for automatic preset, a signal level S from an intermediate frequency stage IF is subjected to A/D conversion 35, and its output is inputted to a microprocessor MPU30. A search stop signal SP is generated when the level of the IF stage is the level S of the broadcast wave of receptionable minimum quality, the MPU35 presets the frequency and the level S when the signal SP is generated to a RAM54, and the level S and the frequency are stored in the RAM54 every time the signal SP is generated during sweeping. After the capacity of the RAM54 is filled, when the sweep is kept and the level S at generation of the signal SP is higher than the level after storage of it to the RAM, the frequency of the high level is replaced into the low level and then the result is preset to the RAM54.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an auto precent system that facilitates the initial setting of preset tuning in an electronically tuned radio receiver.

BACKGROUND ART Auto precent is a function of automatically searching and storing broadcast stations in a region in a preset memory capable of storing a plurality of stations of an electronically tuned radio receiver having a preset channel selection function. This radio receiver with auto precent function starts sweeping from the currently received frequency or the lowest frequency of that band by turning on the start switch, and automatically adjusts the received field strength for each channel that is received sequentially. will be checked. When a broadcast wave that is higher than the noise level and above the level at which the lowest quality broadcast can be received is detected, the broadcast frequency (which specifies the broadcast station or channel mentioned above) or the frequency division ratio N of the PLL synthesizer is stored in the preset memory. Store.

Conventionally, three methods have been considered for this method. One method, as seen in Japanese Patent Application No. 165367/1982, is to sequentially store stations in a preset memory that have been stopped sweeping at one of the electric field strengths that are fixed or can be switched in several stages. However, with this method, if there are more stations than can be preset in one band, the preset memory will be filled before the band goes around the band, and even if a station with a strong electric field is swept after that, it will not be possible to preset it. There are drawbacks.

The other method, as seen in Japanese Patent Application No. 56-169210, is to set the electric field strength level to be detected in advance, pre-select stations with a level higher than that level, and sweep one hunt. If there is space in the preset memory, the detection field intensity level is lowered and the same band is swept again to fill the memory. In this method, if the initial detection level is suitably high, all the stations in the preset memory can be filled with strong electric field stations. However, if the number of stations above the detection level is small, it is necessary to sweep within the same hand two or more times while lowering the detection level, which has the drawback of increasing the time required for auto-presetting.

The remaining one, as seen in Japanese Patent Application No. 59-76816, converts the signal levels sequentially obtained by one search into digital quantities using an A/D converter and compares them with a predetermined level. When the signal level exceeds a predetermined level, the signal level and the received frequency information at that time are sequentially stored in each channel of the preset memory, and after the information is stored in all channels of the memory, a signal level higher than the predetermined level is detected. When the unstored signal level is compared with the stored signal level in memory, and if the unstored signal level is higher, the higher unstored signal level and its received frequency information are compared. In this method, the low-level signal level and its received frequency information are stored in the memory instead of the already stored signal level. In this method, even if there are broadcast waves with a level that exceeds the noise level in one band and the number exceeds the capacity of the preset memory, the preset memory will be filled with only the upper stations with higher field strengths. Moreover, since this operation can be completed by sweeping the pan and dots once, the time required for presetting can be shortened compared to the previous method. However, there are still points to be improved in this method. This is because A/D conversion processing of the signal level and comparison processing between the signal level and a predetermined level are performed every time the received frequency changes during sweeping, so for example, when sweeping the AM band every 9 kHz, Since each of the above processes must be performed several dozen times during one sweep, the sweep time within a band becomes relatively long.

Problems to be Solved by the Invention The present invention solves this last problem of the conventional method, and aims to shorten the sweep time within the hand as much as possible.

Means for Solving the Problems In order to solve the above problems, the present invention has a search function that allows the reception frequency to be changed continuously within a predetermined frequency range, and also has a preset memory and a plurality of preset stations. An electronic device equipped with keys, and when one of the tuning keys is operated, receiving frequency information is read from the corresponding area of the memory, and the receiving frequency is automatically changed based on the read receiving frequency information. In an auto preset method in which a plurality of pieces of received frequency information are written in advance into the memory of a tuned radio receiver, when a search stop signal is generated that is sequentially obtained by one search after creating an auto preset to start the search function. means for sequentially storing the signal level and the received frequency information at that time in each channel of a preset memory, and when a search stop signal is generated after the information has been stored in all channels of the memory, an unstored signal at the time of generation; means for comparing the high level unstored signal level and its received frequency information compared by the means with a previously stored signal level in the memory;
It is provided with means for storing in the memory instead of the previously stored signal level and its received frequency information lower than that level.

The effect search stop signal is a signal output from the intermediate frequency stage of the receiver when it is in a condition to receive broadcast waves with a signal level higher than the signal level that allows reception of the lowest quality broadcast, and a search stop signal is generated during sweeping. Simply stores the signal level and received frequency information when the search stop signal is generated, and even after the preset memory is full, the unstored signal level when the search stop signal is generated is compared with the already stored signal level in the memory. Organize and replace data in memory.

Example FIG. 1 is P L 1. This is a block diagram showing an example of a synthesizer-type electronically tuned radio receiver.
2 is P L 1. (face-locked loop), 3 is a microcomputer system, and 4 is a low-pass filter that outputs a tuning voltage TV. In the radio tuner 1, RF is a high frequency stage coupled to the antenna ANT, MIX is a mixer, ■, 0 is a local oscillator, 1
F is intermediate frequency stage, DET is detection stage, AMP is speaker s
This is an amplification stage that drives p. The received electric field strength (signal level S) and the search stop signal SP are taken out from the intermediate frequency stage IF, the signal level S is sent to the A/D converter 35, and the search stop signal SP is sent to the parallel T1036.
is input. Here, the signal level is determined by converting the output of the intermediate frequency amplification circuit 50 to the detection circuit 5, for example, as shown in FIG.
1 and amplified by the amplifier circuit 52,
The search stop signal is obtained by converting the output of the detection circuit 51 to the amplification circuit 5.
3 and is the output of a comparison circuit 55 which compares the output of this amplification circuit 53 with a reference voltage 54. By changing the input level of the input terminal of the comparator circuit 55 using the transistor 56 and the resistors 57 and 58, which are turned on and off by the search sensitivity switching signal, the search sensitivity is changed between the local state and the distance state.

The microcomputer system 3 includes a microprocessor (MPU) 30, a parallel l1031.32°36,
It is composed of a ROM'33, a RAM34, and an A/D controller 35. Parallel l1031 is an input/output port that gives N value (frequency division ratio) to PLL2, and parallel l103
Reference numeral 2 denotes an input/output port that takes in the ON information of various keys, and parallel 11036 is an input/output port that takes in the search stop signal SP and gives the sensitivity cut signal Q to the intermediate frequency stage IF. In addition to the program shown in FIG. 2, the ROM 33 also stores a radio control program and the like. RAM3
4 has an area used as a preset memory as well as an area used for various routines. The A/D converter 35 converts the analog system level S from the intermediate frequency stage IF into a digital quantity. Note that a control signal 5TART indicates the start and end of A/D conversion.

END is exchanged with the MPU 30.

There are various types of key information to input to the parallel r1032, PRE is the auto preset activation key, ASU is the auto search up key, ASD is the auto search down key, CHo-cr-in is the channel selection key,
L/D is a search sensitivity switching key for switching the search sensitivity between a low state (local state) and a high state (distant state).

FIG. 2 is a flowchart 1- showing an example of an auto-preset process performed by the MPU 30. This program is stored in the ROM 33 and is activated when the activation key PRE is turned on. When the startup key PRE is turned on, the MPU 30 turns on P.
I-L2 is set to the minimum value N min of the N value.

As shown in FIG. 3, Nmin is the N value corresponding to the lowest frequency fmin.

Next, the MPU 30 detects whether or not the search stop signal SP is generated, and if the search stop knob signal SP is not generated, the N value is →-1 and the process returns to the beginning, but the search stop signal is generated. If so, the A/D converter 35 starts A/D sampling, and the A/D
Turn on the timer that determines the sampling time. When this timer turns off after a certain period of time, the A/D at that time
The conversion data (signal level) is taken in, and this signal level and the N value at that time are stored in a preset memory in the RAM 34. At the same time, add 1 to the channel number,
The A/D sampling is completed, the N value is increased by 1, and the process returns to the search stop signal detection step. This is repeated up to channel CHn.

Figure 4(a) shows how the signal level S when the search stop signal SP is generated is stored in the preset memory for six stations.
In this state, the N value (or frequency) of the frequency and frequency are stored. In this state, the frequencies A to F of six stations with search sensitivity or higher, which were detected in sequence by sweeping the band from f min to the middle of Fig. 3, are stored in this order, but the precent operation is ended here. It's not a translation. When the sweep is continued further, a frequency G-M at which a research stop signal is generated is detected until the maximum frequency fma is reached, which is less than the search sensitivity.

Since the preset memory is already filled when the frequency G is detected, CH=n (here n-6). Therefore, the minimum signal level S of cH1 to cHn
Determine min, and store the precented channel of that level as CHB. And this S m
in and the new signal level, and if Sm1n<signal level, delete the N value of CHB and signal level S, organize the channels, and store the new N channel and signal level S in the final channel CHn. .

To explain this in terms of frequency G, as shown in FIG. 4(b), the signal level S of G is 60, which is higher than 40 of A, so 40 and 8 of CH, are deleted and the memory is cleaned up. Then, G and its signal level are written to empty channel CH6 (CHn). Next, when H is detected, C that is smaller than the signal level (55) is deleted in the same manner, and after arranging the memory, H and its signal level are written to channel CH6. FIG. 4(b) shows this intermediate state. The signal levels of r-M detected after this are less than 55 for both J-M, except for the signal level of ① which is 90, which is higher than H. For this reason,
The state in the memory after sweeping up to fmaX is shown in Figure 4 (C
), and instead of H in FIG. 4(b), I, which has a higher signal level, is stored. Repeat this operation until the highest frequency f max (N max for N value) of the band, and finally return to the reception state before pressing the start key PRE, or receive the preset CH or the maximum channel of signal level S. to complete the auto preset process.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various other additions and changes are possible. For example, in areas with congested broadcasting, such as the United States, setting the search sensitivity to the distant state will generate more search stop signals, which increases the signal level measurement.
The comparison frequency and preset memory organization frequency will increase, and the time to sweep within the band will increase. In such cases, press the search sensitivity switch key L/D to set the search sensitivity to the local state, and then All you have to do is press the auto preset activation key PRE.

Further, a step of forcibly switching the search sensitivity to the local state may be added before and after the Nm1n and CHo setting processing shown in FIG. 2. Furthermore, if the frequency of organization in the preset memory during auto preset processing exceeds a predetermined number,
It may be configured such that the information is stored in the RAM 34 and the search sensitivity is automatically changed based on the information when the auto preset activation key is pressed next time.

Effects of the Invention As explained in Section 2, according to the present invention, even if there are broadcast waves with a level exceeding the noise level in the band and the number exceeds the capacity of the preset memory, the electric field is reduced as a result. Since the comparison and rewriting operation is performed so that only the high-order stations with high strength fill the preset memory, it is possible to automatically perform the ideal pre-sent according to the area, and when a search stop signal is generated. This function performs processing such as storing the signal level and received frequency information, comparing it with the stored signal level, replacing it, etc., so when detecting the signal level every time the N value is changed, This has the effect of significantly shortening the sweep time within the hand, that is, the time for auto-preset processing.

Furthermore, the received electric field strength (signal level) of a certain broadcasting station whose center frequency is a frequency equivalent to the frequency division ratio Ni is increased from the characteristic 60 in Fig. 6 to the level shown in the characteristic 61 in the same figure by the AGC action. For example, in an area near a transmitting station where the received field strength of the broadcasting station is large, a considerably large received field strength can be obtained even when the adjacent frequency division ratios are Ni-1 and Ni+1. For this reason, the conventional method (patent application 1983-
76816) has the disadvantage that signal level and reception frequency information when the frequency division ratio is N+-1 and Ni+l are also stored in the preset memory. However, according to the present invention, the search stop signal SP is a narrow band signal,
For example, as shown in Fig. 6, it only occurs near the frequency division ratio N, so the effect is that the signal level and reception frequency information at the frequency division ratio Ni-], Ni→-1 are not erroneously stored in the preset memory. There is also.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of an electronically tuned radio receiver to which the present invention is applied. FIG. 2 is a flowchart 1-1 showing an example of the processing of the MPU 30. FIG. 3 is a block diagram showing an example of the processing of the MPU 30. 4 is an explanatory diagram showing an example of electric field strength distribution, FIG. 4 is an explanatory diagram of Briseno I-memory, FIG. 5 is a block diagram showing an example of a generation circuit for signal level S, search 1-tub signal SP, and FIG. FIG. 2 is a detailed explanatory diagram of the present invention.

Claims (1)

[Claims] It has a search function that allows the reception frequency to be changed continuously within a predetermined frequency range, and is equipped with a preset memory and a plurality of preset tuning keys, and when any of the tuning keys is operated, the corresponding memory is changed. The receiving frequency information is read from the area where the receiving frequency information is read, and the receiving frequency is automatically changed based on the read receiving frequency information. In the preset method, the auto preset activation key that activates the search function, the signal level at the time of the search stop signal generation, and the received frequency information at that time, which are sequentially obtained by one search after operating the activation key, are provided. means for sequentially storing information in each channel of the preset memory; and when a search stop signal is generated after information has been stored in all channels of the memory, an unstored signal level at the time of generation is set as an already stored signal level in the memory. means for comparing, and means for storing the high level unstored signal level and its reception frequency information compared by the means in the memory in place of the lower level stored signal level and its reception frequency information. An auto-preset method for electronically tuned radio receivers.