JPH0332245B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a self-tuning storage receiver using a PLL frequency synthesizer.

Generally, a receiver using a PLL frequency synthesizer can automatically tune by changing the frequency division ratio of the PLL circuit using a sweep circuit and stopping the sweep using the output of an intermediate frequency amplifier or detector. However, a memory circuit is further provided inside the receiver to store the frequency division ratio of the received frequency or information corresponding to the frequency division ratio (hereinafter referred to as "channel selection signal").
A receiver capable of memorizing the received frequency was introduced in 1972.
It has already been developed as seen in No. 32805.
In such a receiver, when the user wants to memorize the received frequency, it is necessary to operate a switch or the like to store it in the storage circuit after the receiver detects a broadcast wave and automatically stops sweeping. This is a receiver that does not require this operation, i.e., when the receiver automatically sweeps to select a station, it also automatically stores it, sweeps to the next station again, and stores it one after another. A receiver (hereinafter referred to as an "automatic tuning memory receiver") has also already been developed. Such an automatic tuning memory receiver is extremely effective in reducing the amount of operation required in a car-mounted receiver and ensuring safe driving of the car. However, the capacity of the storage circuit, that is, the number of storage stations, is limited, and in order to effectively utilize the storage capacity, it is necessary to set criteria for determining whether or not storage is necessary. The problem is how high the level should be set for the strength of the input radio waves. In other words, setting the reference level of the strength of the radio waves to be memorized (hereinafter referred to as the "memory reference level") to a low level radio wave will result in high sensitivity, and the storage capacity will be reduced by storing only the frequency of the broadcast radio waves near the start of the receiver's sweep. On the other hand, if you set the radio wave level too high, the frequency of broadcast radio waves that will be stored will only be the radio waves of a limited number of broadcasting stations with extremely strong radio waves, and you may not be able to use the entire storage capacity. It can happen.

In such cases, it can be resolved by manually adjusting the memory reference level and redoing automatic memory, but
When used in a vehicle, it is necessary to reduce the amount of operation as much as possible in order to drive the vehicle safely. Of course, reducing the amount of operation is useful not only for in-vehicle applications but also for ordinary receivers.

The present invention was invented in view of the problems of the prior art, and it sets the storage reference level to the lowest level, that is, the highest sensitivity, and simultaneously stores the channel selection signal and corresponds to the strength of the broadcast radio wave. It is also equipped with a means for storing information (hereinafter referred to as "radio field intensity signal"), and after the information is stored in the entire storage capacity during the frequency sweep, the signal is transmitted every time a broadcast radio wave with a strength equal to or higher than the storage reference level is detected. , the strength of the broadcast radio wave is compared with the strength of each of the broadcast radio waves already stored, and the strength of the former broadcast radio wave is determined to be the weakest of the latter, that is, the strength of the broadcast radio waves already stored. If the signal is stronger than that of the weakest station, the former's broadcast radio waves, i.e., the channel selection signal and its radio field strength signal, are automatically replaced and stored with only those signals of the latter (first method), or the latter, that is, the weakest station. Eliminates the tuning signal and its radio field strength signal,
Sweeping the entire frequency band using one of the methods (second method) that automatically shifts addresses one by one and stores the information after those storage locations (addresses) where they were stored. By repeating this operation until completion, the purpose is to store radio waves with a strength higher than that of one sweep in all of the memory capacity, and to provide a receiver that makes effective use of the memory capacity and is easy to operate. That is.

Hereinafter, one embodiment will be described in detail with reference to the accompanying drawings.

In FIG. 1, the part surrounded by a broken line indicated by reference numeral 1 is a normal receiver part, and the front end 3 has a built-in PLL frequency synthesizer. The received signal received by the antenna 2, selected by the front end 3, and converted to an intermediate frequency is amplified by the intermediate frequency amplifier 4, detected into an audio signal by the detector 5, amplified by the low frequency amplifier, and then sent to the speaker 7. sent to.

Further, a portion indicated by reference numeral 8 in FIG. 1 includes circuits 10, 11, and 14 for performing automatic tuning, and circuits 9, 12, and 13 for performing a storage operation. The memory circuit 9 stores channel selection signals, that is, the frequency and radio wave intensity of broadcast radio waves, and its operation is controlled by signals 15 and 16a to 16d from a memory control circuit 12, which will be described later.

The sweep circuit 10 sweeps the channel selection signal given to the front end for automatic tuning, and its operation is controlled by the trigger signal 17 sent from the trigger signal generation circuit 11. When the sweep is completed, a sweep completion signal 20 is sent to the trigger signal generation circuit 11 to stop application of the trigger signal 17 from the trigger signal generation circuit 11.

Here, the memory circuit 9 is sent to the front end 3.
The channel selection signal 21 from the sweep circuit 10 and the channel selection signal 22 from the sweep circuit 10 are the former signal 21 when tuning by presetting a reception frequency stored in advance, and the latter signal 21 during sweeping. A signal 22 is sent to the front end.

When a received radio wave is present, the level detection circuit 14 receives a sweep stop signal 23 generated by either the detection signal 18 from the intermediate frequency amplifier 4, the detection signal 19 from the detector 5, or both. This is for generating a digital radio field strength signal 24 or 25 depending on the strength of radio waves.

The detection signals 18 and 19 sent to the level detection circuit 14 are usually only one of the detection signals 18 and 19 in the case of AM reception, and these signals are used that change depending on the strength of the received radio waves. A sweep stop signal 23 and radio field strength signals 24 and 25 are generated. In the case of FM reception, both the detection signals 18 and 19 are used for the sweep stop signal 23, and the detection signal is used for the radio field strength signal. Furthermore, detection signal 1
8 is the same as in the case of AM, and detection signal 1
9 uses an S-curve signal indicating the center of frequency. The radio field intensity signals 24, (25) can be easily generated, and for example, an A-D converter or a priority encoder may be used. The comparison circuit 13 is for comparing the radio field strength signal 24 from the level detection circuit 14 and the already stored radio field strength signal 26 of the broadcasting station from the storage circuit 9. The comparison operation is performed by the comparison command signal 31. If all the storage capacity of the storage circuit 9 is used during the frequency sweep, the broadcast radio waves detected during the subsequent sweep are compared with the weakest broadcast radio waves already stored, and it is determined that the former is the weakest one. If it is strong, a memory replacement signal 27 is sent to a memory control circuit 12, which will be described later.

The trigger signal generation circuit 11 generates a signal that causes the sweep circuit 10 to sweep during automatic tuning, and when a received radio wave is present, a sweep stop signal 23 is input from the level detection circuit 14 and the trigger is triggered. At the same time as the generation of the signal 17 is stopped, a control signal 28 is sent to the storage control circuit 12. Further, this circuit 11 generates a trigger signal 17 again in response to a signal 29 from a storage control circuit 12, which will be described later.

When automatic tuning is performed, the storage control circuit 12 uses the control signal 28 from the trigger signal generation circuit 11 to generate an address designation signal 15 and a signal for performing a storage operation (hereinafter referred to as a "memory operation signal").
16 is sent to the storage circuit 9, and the channel selection signal 30 from the front end 3 at this time (this is the channel selection signal 22 when the sweep is stopped) and the radio field strength signal 25 from the level detection circuit 14 are sent. It is something that makes you remember. In addition, after all the memory is stored in the operating storage capacity of the automatic tuning memory, this memory control circuit 12 is connected to the circuit 11 when automatic tuning is performed.
A comparison command signal 31 is sent to the comparison circuit 13 based on the control signal 28 from the comparison circuit 13 to put it into an operating state, and an address designation signal 15 and a read operation signal 16b are sent to the storage circuit 9 to be stored in the circuit 9. The radio field intensity signal of the stored contents is output from the circuit 9 as a signal 26 and sent to the comparison circuit 13.

In addition, the control circuit 12 also outputs a clear signal 1.
6c and a shift signal 16d, which will be described later when explaining the operation.

One embodiment of the present invention is constituted by such a block circuit, and a series of operations thereof will be explained focusing on the above-mentioned second system.

Although not shown in the figure, when the switch that starts the automatic tuning memory function is pressed to start its operation, the trigger signal 17 is first sent from the trigger signal generation circuit 11 to the sweep circuit 10, and a certain The frequency sweep starts from the frequency. On the other hand, in the level detection circuit 14, the level for generating the sweep stop signal 23, that is, the storage reference level, is set to a considerably low level, and the automatic tuning level of the receiver is set to be highly sensitive. When a broadcast radio wave having a strength equal to or higher than the memory reference level exists, a sweep stop signal 23 is sent from the level detection circuit 14 to the trigger signal generation circuit 11, and the generation of the trigger signal 17 is stopped, and the sweep circuit 10 is used for channel selection. Stop sweeping the signal. At the same time, a control signal 28 is sent to the storage control circuit 12, and in conjunction with this, the control signal 28 is sent to the storage control circuit 12.
2, address designation signal 15 and storage operation signal 16
A is output to the memory circuit 9 to cause the memory circuit 9 to perform a memory operation.

That is, the storage circuit 9 receives the storage operation signal 16.
At the same time as input a, the channel selection signal 30 from the front end 3 indicating the frequency of the tuned broadcast radio wave and the radio field intensity signal 25 from the level detection circuit 14 indicating the radio field strength are input, and the frequency and radio field strength are also input. is stored at the address specified by the address designation signal 15. For example, assume that the memory capacity of the memory circuit 9, that is, the memory addresses are from "1" to "5", and the frequency is 76.3M.
If Hz and radio wave intensity are 4 and the specified address is 1, the frequency and radio wave intensity are appropriately stored at address 1 in the storage circuit as shown in FIG. When the storage operation is completed in this manner, a signal 29 indicating the completion of the storage operation is sent from the storage control circuit 12 to the trigger signal generation circuit 11, and based on this, the trigger signal generation circuit 11 generates the trigger signal 17 again. The sweep circuit 10 resumes sweeping the channel selection signal.

Each time a broadcast radio wave having a level equal to or higher than the storage reference level is detected and a sweep stop signal 23 is output, a similar storage operation is repeated, and the broadcast radio wave is stored for the entire capacity of the storage circuit 9.

During the automatic tuning storage operation, after all storage capacities in the storage circuit 9 have been stored as described above, each time the sweep stop signal 23 is output from the level detection circuit 14 (when the level is higher than the storage reference level). each time a broadcast radio wave is detected) from the memory control circuit 12,
A comparison command signal 31 is sent to the comparison circuit 13, and at the same time an address designation signal 15 and a read operation signal 16b are sent to the comparison circuit 13.
is sent to the storage circuit 9, and the comparison circuit 13 compares the radio field strength signal 26 of the broadcast radio wave already stored in the storage circuit 9 with the radio field strength signal 24 of the broadcast radio wave that has just been automatically tuned.

Assume now that as a result of the automatic tuning storage as described above, five stations with frequencies and radio wave strengths as shown in FIG. 2 are stored. Then, after automatically tuning and storing the 80.2MHz broadcast radio wave, the storage control circuit 12 performs a read operation every time the level detection circuit 14 detects a broadcast radio wave that is higher than the storage reference level, that is, every time it outputs the sweep stop signal 23. The signal 16b and address designation signal 15 are sent to the storage circuit 9, and the comparison command signal 31 is sent to the comparison circuit 13. For example, above
Next to the 80.2MHz signal, if we automatically tune to a broadcasting station with a frequency of 80.8MHz and radio field strength "2", the control signal 28 obtained from the trigger signal generation circuit 11
Therefore, the storage control circuit 12 first sends an address designation signal 15 specifying address 1 and a read operation signal 16.
b is given to the memory circuit 9, and the memory circuit 9 sends out the radio field strength signal 26 of the broadcast radio wave already stored at the address "1" to the comparator circuit 13, and immediately after that, the signal 15 designating the address "2" is sent. and the read operation signal 16b are applied to the memory circuit 9.
The comparison circuit 13 is caused to send out the radio field intensity signal 26 of the broadcast radio wave stored at the address "2".

Then, the storage control circuit 12 gives the comparison command signal 31 and the storage hold signal 32 to the comparison circuit 13 at the timing when these two radio field strength signals 26 are given to the comparison circuit 13, and calculates the radio field strength in both of the radio field strength signals. At the same time, the weaker radio field strength signal resulting from the comparison is temporarily stored in the comparator circuit 13. In this embodiment, the address "2" has a weaker radio field intensity "3", and this is held in the comparator circuit 13.

Thereafter, the storage control circuit 12 outputs an address designation signal 15 specifying address "3" and a read operation signal 1.
6b to the storage circuit 9, and from this, the radio field intensity signal 2 of the broadcast radio wave stored at address "3" is obtained.
6 is sent to the comparator circuit 13, and the comparison command signal 31 and the storage pending signal 32 are again given to the comparing circuit 13, and the radio field intensity of the address "2" which is pending storage is "3" and the radio field intensity of the address "3" is transmitted to the comparison circuit 13. "1" is compared, and the weaker radio field strength signal is stored and held again. In this embodiment, the address "3" has a weaker radio wave intensity of "1", and therefore, this address "3" is stored in the comparison circuit 13 based on the storage reservation signal 32.

Thereafter, this operation is performed over the entire capacity of the memory circuit 9, and the one with the weakest radio wave strength is searched for in the memory circuit 9 (in this embodiment, the broadcast radio wave (78.3MHz) at the address "3" is searched). The radio field strength signal is "1".)

In this way, when the search for the one with the weakest radio wave intensity among all the capacities of the memory circuit 9 is completed according to the instructions from the memory control circuit 12, the memory control circuit 12 compares the comparison command signal 31 again. According to the command, the circuit 13 transmits the radio wave of the 80.8 MHz broadcast radio wave (radio field strength signal 24) which has just been automatically tuned to the radio field strength "1" related to the address "3" with the weakest radio field strength. Compare with intensity "2". As a result of this comparison, since the radio field intensity of the 80.8 MHz broadcast radio wave is greater, the comparison circuit 13 supplies the memory replacement signal 27 to the memory control circuit 12.

Then, when the memory control circuit 12 outputs the address designation signal 15 specifying the address "3", it recognizes that the memory replacement signal 27 has been input, and in conjunction with this, it first outputs the clear signal 16c.
and address designation signal 1 that specifies address “3”.
5 to the memory circuit 9 to clear the broadcast radio field strength signal "1" stored at the address "3" of the circuit 9, and then send the shift signal 16d to the memory circuit 9 to clear the broadcast signal strength signal "1" stored at the address "3" of the circuit 9. The stored information of address "3" is shifted to address "3", and the stored information of address "5" is shifted to address "4", and the radio field strength of the automatically tuned 80.8 MHz broadcast radio wave is "2".
is stored in the address "5" which became a vacant address by the above shift. Then, the storage control circuit 12
A storage operation completion signal 29 is sent to the trigger signal generation circuit 11, and the trigger signal generation circuit 11 restarts generation of the trigger signal 17, causing the sweep circuit 10 to sweep in a higher frequency range.

After the entire storage capacity of the storage circuit 9 has been stored in this manner, automatic tuning storage is performed until the entire frequency sweep is completed. When the entire frequency sweep is completed, a sweep completion signal 20 is sent from the sweep circuit 10 to the trigger signal generation circuit 11 to stop generating the trigger signal 17, and the automatic tuning storage operation ends.

Regarding replacing the stored information, simply replace the weakest of the stored broadcast waves (78.3MHz at address 3 in the above example) with the automatically tuned one (80.8MHz in the above example). (In other words, the above-mentioned first method) also achieves the purpose of efficiently automatically tuning and storing data from strong broadcast radio waves, despite the limited storage capacity.

Since the present invention is configured as described above, it is possible to store in the storage circuit only the radio waves with the strongest radio waves in the order of the frequency of the broadcast radio waves,
Therefore, if the broadcast stations stored in the storage circuit are preset, clear broadcasts can be received.
Furthermore, the comparison means memorizes and holds the radio field strength information of the broadcast radio wave with the weakest radio field strength, and the radio field strength information of the newly received broadcast radio wave is compared with the weakest radio field strength information that has been memorized and withheld. Because of this configuration, only those with strong radio wave intensity can be stored preferentially, and it is an excellent invention that allows storage means with limited storage capacity to be used extremely efficiently.

[Brief explanation of the drawing]

FIG. 1 is a block electrical circuit diagram showing one embodiment of a receiver according to the present invention, and FIG. 2 is an explanatory diagram illustrating an example of storage in a storage circuit. 9: Memory circuit, 10: Sweep circuit, 12: Memory control circuit, 13: Comparison circuit.

Claims (1)

[Claims] 1. Sweeping broadcast waves using a PLL frequency synthesizer, sequentially storing frequency information related to the frequency of broadcast waves automatically tuned by such sweeping, and presetting this stored frequency information. A storage means for storing a predetermined number of frequency information of the broadcast radio waves automatically tuned by the sweep and radio field intensity information indicating the strength of the broadcast radio waves in order of frequency; Radio field strength information of a new broadcast radio wave automatically tuned after all addresses in the storage means have been stored, and radio waves of a broadcast radio wave with the weakest radio field strength among the broadcast radio waves already stored in the storage means. Comparing means for comparing the intensity information with the intensity information until the end of the sweep, and storage control means for controlling the storage means based on the comparison by the comparison means, and the storage control means controls the storage means by the comparison by the comparison means.
When it is determined that the radio field strength of the newly automatically tuned broadcast radio wave is stronger than the radio field strength of the broadcast radio wave with the weakest radio field strength in the storage means, the radio field strength information of the broadcast radio wave with the weakest radio field strength in the storage means and Delete the frequency information and make that address an empty address, and sequentially shift the radio field strength information and frequency information stored in addresses after the empty address to the empty address side to make the final address empty. An automatic tuning storage receiver characterized in that the frequency and radio field intensity information of the newly automatically tuned broadcast radio waves are stored in the final address.