JPS5923648B2 - signal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal display device (hereinafter referred to as a radio wave panoramic display device) that allows the frequency and signal strength of broadcast signals scattered within a broadcast band to be grasped at a glance. Its purpose is to simplify the panoramic display of broadcast signals with high quality.

Generally, displaying radio waves in a panoramic manner makes the operation easier, and in a receiver having a function of switching the bandwidth of the intermediate frequency amplification section, it also serves as a reference for making a decision on switching, and the effect is profound.

However, the scale of the display would be too large to display the entire broadcast band (76 to 90M for domestic FM broadcasts, 531 to 1602 for AM broadcasts), so it is generally necessary to display the area near the receiving point. There is no problem in practical use.

Conventionally, in order to realize such a display, a configuration as shown in FIG. 1 was required.

In the figure, 1 is a high frequency amplifier circuit, 2 is a local oscillator, 3 is a frequency mixer, 4 is an intermediate frequency amplifier circuit, 5 is a detector, 6 is a detection frequency mixer, 7 is a detection local oscillator, 8 is a sawtooth A wave generation circuit, 9 a detection intermediate frequency amplification circuit, 10 a signal level detection circuit, and 11 a display.

However, such a configuration is not suitable for practical use due to the following problems.

That is, for display [this local oscillator, frequency mixer,
It is necessary to provide an intermediate frequency amplification circuit and the like in a separate system, making the configuration complicated.

The detection local oscillator 7 performs frequency sweep using the output signal of the sawtooth wave generation circuit 8, but its frequency accuracy and linearity are poor, so the display 11 uses an expensive analog display such as a cathode ray tube. Display accuracy must be obscured by using a device.

Since the high frequency amplifier circuit 1 remains tuned to the receiving point, due to its selection characteristics, the further away from the center point of the display, the more errors occur in the signal strength, and the display bandwidth is extremely limited. There was a problem.

The present invention provides a signal display device of high quality and simple construction by making full use of synthesizer type electronic receivers that have recently become established in the market.

FIG. 2 shows an example of its configuration. 11' is a digital solid state display (e.g. light emitting diode, liquid crystal).

12 is a frequency synthesizer circuit, 13 is a receiving frequency control circuit, and 14 is a memory circuit.

Although the operating principle of the frequency synthesizer circuit 12 using a phase-locked loop or the like is well known and is omitted here, the oscillation frequency of the local oscillator 2 and the high-frequency amplifier circuit are determined according to the frequency code given from the receiving station oscillation number control circuit 13. Needless to say, it has the role of determining the tuning point of No. 1.

Generally, when selecting a channel using a synthesizer type receiver, sweeping is performed stepwise at fstep intervals as shown in FIG.

Specifically, fstep is 10 for domestic FM reception.
0KHz, and 9K)h for AM reception.

In this example, the reception frequency control circuit 13 generates a frequency code so as to perform a high-speed sweep at f'5 step intervals over a range of Δf as shown in FIG. The input signal level is stored in the memory circuit 14 via the detection circuit 10.

Generally, fstep (!: fζtep is set to the same frequency, but their magnitude relationship is arbitrary depending on the frequency interval requirements at the time of display.

The output signal of the memory circuit 14 is transmitted to the display 11'.
As a result, a display as shown in FIG. 4, for example, can be obtained.

With such a configuration, the problems in the conventional method described above can be solved.

That is, there is no need to newly install a local oscillator two-frequency rationalizer or intermediate frequency amplification circuit.

Furthermore, since a synthesizer method is used for frequency sweeping, frequency accuracy is high, and therefore it is possible to display at an accurate position using a relatively inexpensive solid-state display.

Further, since the sweep is also synchronized with the high frequency amplifier circuit 1, there is an advantage that no display error occurs regardless of the sweep range.

Note that the display is the output of the memory circuit 14, and the signal level is not displayed in real time, but as shown in Figure 3, the signal level is detected by high-speed sweeping every time the reception point is changed (including when selecting a preset station). There is no practical problem because the signal level is rewritten to the signal level immediately before the start.

Furthermore, since the signal level at the receiving point can be detected at all times, the signal level at the center of the display shown in FIG. 4 can of course be displayed in real time.

As described above, according to the present invention, it is possible to easily display a broadcast signal in a high-quality manner by taking advantage of the characteristics of a digital receiver.

[Brief explanation of drawings]

Fig. 1 is a block diagram for realizing a conventional radio wave panoramic display device, Fig. 2 is a block diagram showing an example of a configuration for realizing the signal display device of the present invention, and Fig. 3 is a block diagram for realizing the signal display device of the present invention. FIG. 4, which is an explanatory diagram of the sweep operation, is a diagram showing an example of display on a solid-state display of a matrix structure used in the same device. 1...High frequency amplification circuit, 2...Local oscillator, 3...Frequency mixer, 4...Intermediate frequency amplification circuit, 10...・Level detector, 11
... Display device, 12 ... Frequency synthesizer circuit, 14 ... Memory circuit.

Claims (1)

[Claims] 1 Reception frequency control that gives a frequency code to the frequency synthesizer circuit so that each time the reception frequency is set in a frequency synthesizer type receiver, a frequency code is given to the frequency synthesizer circuit so that reception is swept over a predetermined frequency range at predetermined frequency intervals around the set reception frequency. a memory circuit for storing the received signal strength during the sweep reception as the frequency interval, and a memory circuit for reading out the stored contents of the memory circuit to indicate the received signal strength at each predetermined frequency interval within the frequency range. A signal display device comprising: a dimensional matrix display device.