JPH04122117A - Electronic tuning type radio receiver - Google Patents

Abstract

PURPOSE:To allow this receiver to tune a desired frequency quickly by calculating a difference between an intermediate frequency at complete tuning and an intermediate frequency at automatic channel selection scanning and matching the tuning frequency to the frequency being the sum of the difference and the scanning frequency. CONSTITUTION:Suppose that channel selection scanning is started at a time 41A, then a series of processing is implemented at a time 39 and the processing is progressed up to a time 41B and then a scanning frequency is increased by 4 steps. Series of processings 31-38 are started again in this state, and suppose that a reception station exists between frequencies 40B and 40C, then an IF counting section 4b an intermediate frequency being a difference between a local oscillating frequency corresponding to a tuning frequency and an antenna input reception frequency at an IF count time zone 36. Then a calculation section 6c calculates a difference DELTAfIF being a difference between the measured value and a complete tuning frequency, and the difference DELTAfIF is controlled to be made zero. Thus, the scanning tuning frequency and the antenna input frequency are completely tuned.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electronically tuned radio receiver, and in particular has a so-called automatic tuning function that automatically matches the tuning frequency to a received signal input from an antenna. It is connected to an electronically tuned radio receiver.

[Prior Art] FIG. 4 is a schematic configuration diagram showing a conventional electronically tuned radio receiver.

In Fig. 4, a receiving antenna (1), a part of an AM tuner for converting an AM high frequency signal to an intermediate frequency (2), an AM-IF detection section (3) for intermediate frequency detection, and an A for low frequency amplification are shown.
P amplifier section (4) and speaker for audio output (5)
This constitutes a boat-based AM reception system. The microcomputer section (6) is composed of a suitable microcomputer, a switch section (7) for adding various instruction signals, a PLL section (8) for electronic tuning, and a display consisting of a fluorescent display tube, etc. section (9) is connected. This microcomputer section (6) sends a frequency division ratio signal to the PLL section (8) in order to set the tuning frequency of the AM tuner part (2), and also sends a reception frequency for automatic tuning as described later. control the scanning of Furthermore, 5D (Station Detect) is used to detect the presence or absence of a receiving station during automatic channel selection.
It is equipped with an r input section (ε&). In addition, in order to increase the reliability of determining the presence or absence of a receiving station, an IF counting section (6b) 1 for measuring an intermediate frequency, which is similar to the intermediate frequency detection section (3), may be used in combination.

FIG. 5 is a time chart for explaining the automatic tuning operation of the conventional electronically tuned radio reception product. This figure 5 shows that when scanning is performed at a fixed frequency interval,
The time spent at one frequency point (28) and the various time expansions (21) (22) (23) (
24) (25) (26) (27) are shown. These various time periods are chattering prevention time periods (21)
, mute first out time period (22>, display change time zone (2)
3), lock wait time period (24), SD wait time leap period (25), post-mute time period (27), etc. Furthermore, in a radio receiver equipped with an IF counting section (6b), an IP counting time period (26) is further added.

In an electronically tuned radio receiver, if the AM receivable band from 522 KHz to 1710 KHz is frequency scanned using the minimum frequency interval IKI (z), the above-mentioned various time periods are required. Just one round,
It takes about 1.5 to 2 minutes, and is not practical as an automatic channel selection function.

For this reason, the total number of automatic tuning scanning frequencies can be reduced by making the automatic tuning scanning frequency interval match the above channel space for each region where the channel space has been unified, and - making it practical to scan the scanning time. It was normal to manufacture radio receivers that were shortened to the extent that they could be used in each region, and to provide them separately. i.e. 10KHz
The company provided receivers with a 10 KHz scanning interval for the channel space areas, and receivers with a 9 kHz scanning interval for the 9 kHz channel space areas.

In addition, in order to solve the above-mentioned problem, a radio receiver using a special scanning method as shown in Japanese Patent Application No. 1-241733 has been developed for the purpose of being able to be used commonly in areas with different channel spaces. In recent years, the provision of such services has also been implemented. The automatic channel selection method disclosed in Japanese Patent Application No. 1-241733 will be explained below. FIG. 6 shows a circuit configuration for performing this automatic channel selection. (1) (2) (4
) to (9) are the same as in FIG.

The 8N-IF detection section (3^) includes an IF filter (3m) (3b) for creating an SD flaw signal for detecting receiving stations, and a switch (3c) for switching these.
The bandwidth of a) is set close to the wide scanning frequency interval described below, while the bandwidth of the IF filter (3B) is set close to the narrow scanning frequency interval described below. When automatic channel selection is started now, the scanning frequency interval is set wide (referred to as wide scanning) and scanning begins. here,
If the receiving station is within this frequency range, an IP filter (3
a) and is input to the SD input section (6a). Then, the microcomputer section (6) narrows the scanning frequency interval so as to scan finely within this frequency range (referred to as narrow scanning), and at the same time, the switch (3c) is switched and the SD flaw signal IP filter (3b) The signal passes through and is input to the SD input section (6a). In this way, it is possible to construct a radio receiver with automatic tuning that can be used commonly in areas with different channel spaces without significantly reducing the intra-band scanning speed.

However, to implement this, an IF filter (3
SD consisting of a), (3b) and switch (3c)
This poses a cost problem because it requires band switching means.

[Problem to be solved by the invention] Since the conventional electronically tuned AM radio receiver is configured as described above, it can be used commonly in regions with different channel spaces and has a practical automatic selection function. The problem of constructing an electronically tuned radio receiver with station speed is the increased manufacturing cost and the ability to use it between regions with different channel spaces without increasing the cost. When attempting to construct an electronically tuned radio receiver, there was a problem in that the automatic tuning speed decreased significantly, making it impractical.

This invention was made to solve the above-mentioned problems, and has a practical automatic tuning speed, can be used commonly across channel spaces, and has a simple configuration that reduces manufacturing costs. The object of the present invention is to obtain an electronically tuned radio receiver that does not involve an increase in the temperature.

[Means for Solving the Problems] An electronically tuned radio receiver according to the present invention is an electronically tuned radio receiver that includes an AM broadcast receiving function section and a microcomputer section. a scanning means for scanning, a means capable of measuring an intermediate frequency included in the AM broadcast receiving function section, a measured value of the intermediate frequency during the scanning, and a tuning frequency at this time;
The receiving station frequency inputted from the antenna is determined, and the tuning frequency of the AM broadcast receiving function section is adjusted to the determined frequency.

[Function] In this invention, the manufacturing cost is reduced by calculating the difference between the intermediate frequency during complete tuning and the intermediate frequency during automatic tuning scanning, and adjusting the tuning frequency to the value obtained by adding the difference to the scanning frequency. Even in environments where the channel space is not fixed, it is possible to reliably determine the receiving station without increasing the channel space.
A radio receiver can be quickly tuned to that frequency.

[Embodiment] Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. 1st
The figure is a schematic configuration diagram showing an embodiment of the present invention. 1st
In the figure, (1) to (5) and (7) to (9) are the same as the conventional device described above. (6^) is a microcomputer section, which includes an IF count section (6b) and an IP count section (6b).
The frequency measured in b) and the intermediate frequency when fully tuned is 450
KHz difference calculation unit (6c) and tuning frequency setting unit (6c)
6d), and this frequency setting part (6d) is 450KH.
z performs processing as described later based on the output of the calculation unit (6c), and operates to set the tuning frequency.

FIG. 2 is a time chart diagram for explaining the automatic channel selection operation of FIG. 1. FIG. 2 (^) is a diagram showing the relationship between the elapsed time and the tuning frequency during automatic channel selection scanning at frequency intervals of 10 KHz. In Figure 2 (^), (41)
represents the elapsed time, and (40) represents the tuning frequency. The time spent for each frequency step during scanning (39) is shown in Figure 2 (B).
) includes various time periods as shown in That is,
In Figure 2 (B), chattering prevention time period (31)
, Mute first out time period (32), Display change time period (3
3), Lock wait time period (34), IF count wait time period (35), IF count time period (36),
450KHz -IF count frequency calculation time period (
37), post-mute time period (38), etc. At time 0 (39), where it is assumed that the channel selection scan starts from time (41^) in Figure 2 (^), the above-mentioned process is performed. It is assumed that the scanning frequency is increased by 4 steps (Hz = 40 KHz for 4 steps x 10) and progresses to time (41B). Here, the series of processing from (31) to (38) starts again, but if there is a receiving station between frequency <40B> and (40e), the IF count time period (36)
, the IF counting section (6b) (FIG. 1) measures the intermediate frequency which is the difference between the local oscillation frequency corresponding to the tuning frequency and the antenna input receiving frequency. As is well known, the local oscillation frequency here means the tuning frequency plus the intermediate frequency at the time of complete tuning. Next, the calculation section (B
e) According to (Fig. 1), the measured value and the perfectly tuned frequency 45
The difference ΔflF from 0 KHz is calculated. As mentioned above, −
In an AM radio receiver for fishing on a boat, the relationship between the intermediate frequency f+y, the local oscillation frequency f6@e, and the antenna input frequency fRF is expressed by the following equation.

f,,=f,,c −f,, (1
) Here, the local oscillation frequency f omc is set to a value obtained by adding the intermediate frequency (generally 450 KHz) when completely tuned to the tuning frequency. Therefore, if the tuning frequency during channel selection scanning matches the antenna input frequency, the intermediate frequency f+v is 450KH from the above formula (1).
z, and the calculation section (6c) calculates 8ftp=f+r-450
Outputs the value KF1z=450KHz-450KHz=O(2). In other words, if the value of Δf□ is 0, it means that the scanning tuning frequency and the antenna input frequency are perfectly tuned.

Next, consider the case where the antenna input frequency is not equal to the scanning frequency. Assume now that the antenna input frequency is IKHz lower than the scanning frequency. The intermediate frequency FX2 at this time is expressed by the formula (1), and the output of the calculation section (6c) is ΔL-=450 451=1 (KHz
) (4), that is, this value of 8 flF represents the deviation of the antenna input frequency with respect to the scanning frequency, and the tuning frequency is reset to the value obtained by adding the frequency difference in equation (4) above to the scanning frequency. By doing so, the radio receiver can be perfectly tuned to any antenna input frequency.

Note that in the above embodiment, 5D (Station
Detector) signal is not used, but as shown in FIG. 3, the above embodiment may also be configured to use an SD double signal, that is, FIG. 3 shows an SD input section in the microcomputer section (6B). The configuration is exactly the same as the embodiment shown in FIG. 1 except that (6a) is provided. The operation in this case will be explained below.

In the embodiment shown in FIG. 1, the intermediate frequency f IF created by the antenna input input during scanning and the local oscillation frequency at that time is measured regardless of the level of the antenna input. Therefore, the automatic channel selection operation will work even when the antenna input is weak and the reception condition is poor in the electric field. In practice, it is desirable not to tune into such electric fields with poor reception conditions, but to select only receiving stations with high electric field levels and good reception conditions.The embodiment shown in FIG. 3 is as described above. This is a response to these demands. That is, the SD input section (6a) corresponds to a certain level of the antenna input as in the conventional system, and outputs an identification signal when it is higher or lower than that level. (This will be referred to as the SD double signal active when the SD double signal is applied.) Only when the SD double signal becomes active, the scanning frequency is completely tuned to the antenna input frequency from the measurement of the intermediate frequency, as shown in the first embodiment. It performs a series of actions. This makes it possible to selectively select only those stations with good reception among the unreceivable stations. In this case as well, as in the first embodiment, there are advantages such as the channel space can be shared between different regions, the channel selection speed is high enough for practical use, and there is no cost increase compared to the conventional method. It goes without saying that you can get it.

[Effects of the Invention] As described above, according to the present invention, in an electronically tuned radio receiver including an AM broadcast receiving function section and a microcomputer section, a scanning means for continuously scanning a tuning frequency at a certain frequency interval is provided. and a means for measuring an intermediate frequency included in the AM broadcast receiving function section, and determining a receiving station frequency input from the antenna from the measured value of the intermediate frequency during the scanning and the tuning frequency at this time. , and a means for adjusting the tuning frequency of the AM broadcast receiving function section to that frequency, so that it can be commonly used in areas with different channel spaces, and the tuning speed is high enough to be of practical use. This has the effect that a radio receiver with functions can be obtained at low cost with a simple configuration and without an increase in manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of an electronically tuned radio receiver according to the present invention, FIG. 2 is a time chart diagram for explaining the tuning operation of FIG. 1, and FIG. A schematic configuration diagram showing another embodiment of a tunable radio receiver,
FIG. 4 is a schematic configuration diagram showing a conventional electronically tuned radio receiver, and FIG. 5 is a 4r5! FIG. 6 is a time chart diagram for explaining the channel selection operation of i, and is a schematic configuration diagram showing a conventional electronically tuned radio receiver. In the figure, (2) is part of the AM tuner, and (3) is the AM tuner.
-IF detection section, (4) is AP amplifier section, (6^). (6B) is a microcomputer section, and (8) is a PLL section. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claim] An electronically tuned radio receiver including an AM broadcast receiving function section and a microcomputer section, comprising: scanning means for continuously scanning a tuned frequency at a certain frequency interval; determining a receiving station frequency input from the antenna from the measured value of the intermediate frequency during the scanning and the tuning frequency at this time; An electronically tuned radio receiver comprising means for adjusting the tuning frequency of the radio receiver.