JPS6318194Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wavelength display device that displays a received frequency using a wavelength such as a meter band.

In shortwave broadcasting, the frequency band in which international broadcasting is concentrated is expressed by wavelength, and for example, the band from 11.7 to 11.975 MHz is called the 25m band. For this reason, the dial display of conventional receivers also displays the meter band along with the reception frequency, as shown in FIG.
In other words, in Figure 1, the dial display of the shortwave broadcasting SW shows frequencies such as 8MHz, 12MHz, etc.
Predetermined meter bands such as 31m, 25m, etc. are displayed by printing or the like. However, with this method of mechanically displaying the meter band by printing, etc., the display becomes inaccurate due to errors in the dial scale, installation errors in the dial scale plate and pointer, temperature characteristics of the circuit, etc. Display tends to be inaccurate near the upper and lower limits of width.

The present invention solves the above problems by displaying the meter band purely electronically.Examples of the present invention will be described below with reference to the drawings.

FIG. 2 shows a case where the present invention is applied to a receiver having a digital synthesizer tuner.

In the figure, a signal received by an antenna 1 is tuned by a high frequency circuit 2, and the tuned signal is mixed with a VCO (voltage controlled oscillator 3) forming a local oscillator to become an intermediate frequency signal of a predetermined frequency. This intermediate frequency signal is amplified by an intermediate frequency amplification circuit 4 and then detected by a detection circuit 5 to become an audio signal. VCO3 is a PLL along with PLL circuit 6 and frequency divider 7.
(phase locked loop). still,
The PLL circuit 6 includes a reference crystal oscillator, a frequency divider, a phase comparator, a low frequency amplifier, an amplifier, and the like. When a receiving station is selected by the channel selection button 8, a controller 9 composed of a microcomputer or the like sets the frequency division ratios of the frequency divider 7 and the frequency divider of the PLL circuit 6 in accordance with the receiving frequency. This controls the frequency of VCO3. Also at this time, the display circuit 10
The received frequency is displayed by .

The controller 9 obtains data S _D indicating the reception frequency from the PLL circuit 6, and reads out the meter band for the reception frequency from the memory 11 based on this data. The memory 11 stores meter band data for reception frequencies as shown in the following table, for example.

120m band...2.3~2.498MHz 90m 〃 3.2~3.4 75m 〃 3.9~4.0 60m 〃 4.75~5.06 49m 〃 5.95~6.2 41m 〃 7.1~7.3 31m …… 9.5-9.775 25m 〃 ...11.7-11.975 19m 〃 ...15.1-15.45 16m 〃 ...17.7-17.9 13m 〃 ...21.45-21.75 11m 〃 ...25.6-26.1 The data read from the memory 11 is sent to the controller 9. The meter band is displayed by being applied to the display circuit 12 via the meter band. At the same time, the transistor 13 is made conductive to cause the LED (light emitting diode) 14 to emit light, thereby indicating that the station currently being received is in a certain meter band. still,
Provide the same number of LEDs as the meter bands, and use the data read from memory 11 to respond.
Only the LEDs may be made to selectively emit light.

FIG. 3 shows a flowchart of the microcomputer that constitutes the controller 9. Note that the meter band is based on the table above, and as an example, the receiving frequency is
The case of 5MHz and 60m band is shown.

In the figure, when a reception frequency of 5MHz is input in step 1, first in step 2 the reception frequency is changed to the lower limit frequency of the first stage in the table.
It is determined whether the frequency is 2.3MHz or higher. In this case, the frequency is 2.3MHz or higher, so proceed to step 3.
Here, it is determined whether the lower limit frequency of the next stage is 3.2 MHz or higher. Then in step 4 3.9M
Hz and further compared with 4.75MHz in step 5. The process then proceeds to step 6, where it is compared with the lower limit frequency of the 60m band, 5.95MHz. Here, the judgment is "NO" and the process proceeds to step 7.
Therefore, it is determined whether the upper limit frequency of the 60m band is below 5.06MHz. Step 7 “YES”
Based on the judgment of output port 8, the reception frequency is 60m.
Outputs data indicating that it is in the band.

If the reception frequency is higher than 5MHz and in the meter band shorter than the 60m band, proceed to step 6.
The process then proceeds to step 9, where it is compared with 7.1MHz, and the following steps proceed based on the same determination as described above. If the receiving frequency is lower than 5MHz and in a meter band longer than 60m band, proceed to step 2~
5, the result is a "NO" determination, and the process proceeds to the next step where the frequency is compared with the upper limit frequency of that meter band.

As described above, the receiving frequency and the lower limit frequency of each meter band are sequentially compared, and when a "NO" determination is made, the process proceeds to a step in which the lower limit frequency is compared with the corresponding upper limit frequency. By performing such processing, output data indicating the meter band can be obtained.

In this example, the case of shortwave broadcasting was described.
The reception frequencies of FM broadcasts, medium wave broadcasts, and broadcasts in other bands may be displayed in wavelengths.

As described above, the present invention is constructed so that the data S _D indicating the reception frequency is obtained from the PLL circuit that controls the oscillation frequency of the local oscillator 3 according to the reception frequency, and the wavelength data corresponding to the frequency is stored. The present invention relates to a wavelength display device characterized in that a storage device 11 is provided, and corresponding wavelength data is read out from the storage device based on data indicating the reception frequency.

Therefore, according to the present invention, since wavelength display is performed purely electronically, accurate display can be performed. Furthermore, in the case of a receiver using a synthesizer tuner, data indicating the reception frequency can be easily obtained using a PLL circuit, so it is only necessary to add a simple circuit.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the dial display part of the receiver;
FIG. 2 is a circuit block diagram showing an embodiment of the present invention.
Figure 3 is a flowchart of the microcomputer. In addition, in the symbols used in the drawings, 3...
...VCO, 6...PLL circuit, 9...controller,
11...Memory.

Claims (1)

[Scope of utility model registration request] Data indicating the reception frequency is obtained from a PLL circuit that controls the oscillation frequency of the local oscillator according to the reception frequency, and a storage device is provided in which wavelength data corresponding to the frequency is stored, and the data indicating the reception frequency is stored. 1. A wavelength display device, wherein corresponding wavelength data is read out from the storage device based on the wavelength data.