JPH0330332B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a radio wave type conversion receiver, and more particularly to a radio wave type conversion receiver that converts a received FM signal into an AM signal.

[Technical background of the invention and its problems]

When guiding several dozen participants (hereinafter simply referred to as participants) around famous places, historical sites, factories, etc., the guide uses a loudspeaker to keep track of the participants. However, the sound from loudspeakers is difficult to hear in noisy environments, and creates noise for third parties in quiet environments, so guide receivers with earphones are distributed to participants, and guides use portable transmitters to communicate with the participants. A method has been proposed to provide guidance. However, since broadcasting using radio waves as a medium by unqualified persons is prohibited regardless of whether it is portable, portable, or fixed, the guide is based on the provisions of Article 6, Paragraph 1 of the Radio Law Enforcement Regulations (Exemptions from the Radio Law). Broadcasting will be done using satisfactory high-frequency radio waves (hereinafter referred to as weak radio waves).

A medium wave band amplitude modulation receiver (hereinafter simply referred to as an AM receiver; also referred to as a medium wave band AM receiver only when it is necessary to distinguish it from those for other bands) can perform the above guidance reception without changing the circuit. You can get the functions of the machine.
AM receivers have few operating parts, are easy to handle, and are inexpensive, so if you give them to participants as a souvenir after the tour ends, they can be used for AM reception at a later date.
It becomes a profitable advertising product. However, for guidance
If an AM transmitter is made for portable use, it has drawbacks such as the inability to utilize medium wave numbers due to the shape of the antenna.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a radio wave type conversion receiver that can use a medium wave band amplitude modulation receiver as a guidance receiver.

[Summary of the invention]

The radio wave type conversion receiver according to the present invention receives
It is designed to convert FM signals to AM signals.
The converted AM signal is sent to the antenna circuit of the medium wave band amplitude modulation receiver via electromagnetic coupling. The medium wave band amplitude modulation receiver has the normal general broadcast reception function,
Do not install special signal exchange means such as plugs or jacks between the radio wave type conversion receiver and the radio wave type conversion receiver.

[Embodiments of the invention]

Hereinafter, one embodiment of the radio wave type conversion receiver according to the present invention will be described in detail with reference to the drawings.

In FIG. 1, 1 is a radio wave type conversion receiver. The radio wave type conversion receiver 1 is the guidance FM transmitter 2
An FM signal F _i transmitted at a power within 15 μV/m at a distance of 100 m from the antenna 2a is inputted to the terminal 1b via the antenna 1a. The FM signal F _i input to terminal 1b is sent to RF module 3a and detector 3b.
The signal is converted into an audio signal F _a via an FM receiver 3 consisting of the following, and sent to an AM modulator 4. AM modulator 4
Then, the carrier wave oscillated by a local oscillator is converted into an audio signal.
The AM signal f _p is amplitude modulated by F _a and sent out by the high frequency output circuit 6 . The high frequency output circuit 6 is a tuned circuit formed by a coil _L1 and a capacitor _C1 . AM receiver storage section of the radio wave type conversion receiver 1 shown in Fig. 2
When the AM receiver 7 is housed in IC, the coil L ₂ of the antenna circuit consisting of the coil L ₂ of the AM receiver 7 and the capacitor C ₂ is M-coupled with the coil L ₁ . Coil L ₂
and coil ₁ are M-coupled, so the AM signal F ₀ is AM
It becomes an audio signal via the detection amplifier circuit 7a of the receiver 7 and the earphone 7b.

The FM signal F _i is either VHF or
UHF band.

A guide carrying a guide transmitter 2, a radio wave type conversion receiver 1, and an AM receiver 7 will send and receive FM signals F _i while traveling to famous places, historical sites, factories, etc. The FM signal F _i has less fluctuation in the audio signal F _a due to changes in electric field strength, and is more advantageous in terms of noise than the AM method. It is also possible to receive even weak radio waves.

〔Effect of the invention〕

The radio wave type conversion receiver according to the present invention houses a frequency modulation receiving means, a medium wave band amplitude modulating means for modulating the audio signal obtained by the frequency modulated signal receiving means into a medium wave band amplitude modulation signal, and an AM receiver. Since the structure is equipped with an AM receiver storage means, the feature is that the FM signal received by the radio wave type conversion receiver is converted to an AM signal and sent to the medium wave band AM receiver via electromagnetic coupling. are doing. Therefore, the present invention has the advantage that it can be used as a guidance receiver without changing the circuit or structure of a normal radio receiver.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a radio wave type conversion receiver according to the present invention, and FIG. 2 is a perspective view of the radio wave type conversion receiver according to FIG. In the figure, 1 is a radio wave type conversion receiver, 1a and 2a are antennas, 1b is a terminal, 1c is an AM receiver housing, 2 is a guidance transmitter, 3 is an FM receiver, 3a is an RF module, and 3b is a detection unit. 4 is an AM modulator, 5 is a local oscillator, 6 is a high frequency output circuit, 7 is a medium wave band
In the AM receiver, 7a is a detection amplifier circuit, 7b is an earphone, C ₁ and C ₂ are capacitors, and L ₁ and L ₂ are coils.

Claims (1)

[Claims] 1. Frequency modulation signal receiving means for receiving a frequency modulation signal and generating an audio signal; medium wave band amplitude modulation means for modulating the audio signal obtained by the frequency modulation signal receiving means into a medium wave band amplitude modulation signal; A medium wave band AM receiver storage means provided to integrate a band AM receiver and a radio wave type conversion receiver, and transmits an amplitude modulated signal to the medium wave band AM receiver via electromagnetic coupling. A radio wave type conversion receiver characterized by being configured as follows.