JPH10271076A - Radio receiver - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a radio receiver capable of efficiently switching each function of stereo output, monaural output, and stereo local. SOLUTION: In this radio receiver, a stereo local which demodulates and outputs a stereo with reduced reception sensitivity and a stereo D which demodulates and outputs stereo without decreasing the reception sensitivity.
X and a monaural DX that demodulates and outputs a monaural signal without lowering the receiving sensitivity include a menu button 11 and a set button 12.
Is switched by. When the stereo DX is set, only the cursor 21 is displayed, and the others are not displayed. In the case of monaural DX, MONO22 is displayed. In the case of stereo local, LOCAL 23 is displayed. Each function is cycled by the set button 12 from stereo DX to monaural DX to stereo local to stereo DX.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver having a stereo reception function, and more particularly to a radio receiver having a stereo / monaural switching function.

[0002]

2. Description of the Related Art Conventionally, stereo FM (Frequency Modu
lation) Radio receiver for receiving broadcast, stereo F
2. Description of the Related Art There is known a tape cassette recording / reproducing apparatus having an M broadcast radio receiving function, which has a function of switching between a stereo audio signal and a monaural audio signal to output audio. The reason that a stereo FM broadcast can be switched and output between a stereo audio signal and a monaural audio signal in this manner is that, for example, the received FM broadcast has a low electric field strength and a stereo output has a lot of noise and makes it difficult to hear sound. Even at this time, it is possible to hear a sound with little noise by making the output monaural. That is,
This is because, even with the same electric field strength of FM broadcasting, a monaural audio signal can be heard with less noise than a stereo audio signal.

[0003] Also, there is known a conventional radio receiver or the like having a function of receiving a FM broadcast by switching to a so-called stereo local function when outputting a stereo audio signal. The stereo local function is a function of attenuating a received signal of FM broadcast received from an antenna by a fixed amount and supplying the signal to a demodulation circuit. The reason why demodulation is performed after attenuating the received signal in the stereo local function is to remove noise called buzz.

[0004] In this buzz, when FM broadcast of a desired frequency is demodulated, broadcasts of frequencies in the vicinity of the buzz are mixed, resulting in sound noise such as a boon and output from a speaker. This buzz is performed, for example, by AGC (Auto Gai
n Control) This occurs when the adjustment is inappropriate and the input signal is too large. Therefore, if an attempt is made to receive the FM broadcast in a place near the radio tower, the electric field strength is large and this buzz occurs.

[0005] That is, this stereo local function,
This function reduces the receiving sensitivity in places where the electric field strength is large, and allows FM broadcasts to be heard with good sound without buzz. Such a radio receiver or the like having a function of switching between a stereo audio signal and a monaural audio signal and a function of switching between stereo locals is provided with two two-contact changeover switches for switching these functions. The first switch is a switch for switching between a stereo audio signal and a monaural audio signal for output, and the second switch is a switch for switching between a stereo output with normal sensitivity and a stereo local function with reduced sensitivity. It is.

The switching outputs of the first and second selector switches are supplied as digital data of 0 and 1 to a system controller which controls each circuit of the radio receiver.

[0007]

However, such a function of switching between stereo and monaural audio signals and a function of switching between stereo locals can be selectively switched by the user according to the state of radio waves. That is, when the electric field strength of the FM broadcast is low, the output is switched to the monaural output. When the electric field strength of the FM broadcast is high, switching to stereo local is performed. And
When the electric field strength of the FM broadcast is normal, the output is switched to the stereo output. Therefore, when the electric field strength of the FM broadcast is high, it is not necessary to switch to the monaural output, and it is only necessary to switch these functions in three stages according to the electric field strength.

However, in a conventional radio receiver,
As described above, since the switching is performed using the two switching switches, only two switching patterns, that is, a switching pattern of stereo and monaural and a switching pattern of stereo and stereo local can be selected.

Therefore, two types of liquid crystal display units (LCDs) for displaying the currently set functions are required corresponding to the two changeover switches. Further, the system controller also needs to control two output ports, an output port for switching reception sensitivity and a port for switching between stereo and monaural, in accordance with the switching of the respective changeover switches. That is, a control program for controlling different output ports for each changeover switch is required.

[0010] The present invention has been made in view of such circumstances, and has as its object to provide a radio receiver capable of efficiently switching each function of stereo output, monaural output, and stereo local. .

[0011]

In order to solve the above-mentioned problems, a radio receiver according to the present invention includes a mode switching key for switching an operation mode, and a radio receiver in an operation mode switched by the mode switching key. A setting key for setting functions, a receiving antenna for receiving stereo audio broadcasting,
An attenuation circuit that attenuates the signal level of the received signal of the stereo audio broadcast; an audio signal demodulation circuit that demodulates the received signal; and a stereo audio signal or monaural audio signal generated from the received signal demodulated by the audio signal demodulation circuit. When a stereo function is set by the setting key in the switched radio reception mode and a stereo function is output, a stereo sound signal is output from the stereo demodulation circuit, and a monaural function is set by the setting key. If the stereo demodulation circuit outputs a monaural audio signal, and if the stereo local function is set by the setting key, the audio signal demodulation circuit demodulates the stereo audio broadcast whose signal level has been attenuated by the attenuating circuit. A stereo audio signal is output from the stereo demodulation circuit. Characterized in that it comprises a control circuit for.

In this radio receiver, the operation mode switching key is used to switch to the radio reception mode, the setting key is used to set a monaural function, a stereo function, and a stereo local function, and the monaural output signal is set according to the signal level of the received stereo audio broadcast. , And outputs a stereo output signal and a stereo output signal whose reception sensitivity is attenuated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A recording / reproducing apparatus for a tape cassette with a radio receiving function to which the present invention is applied will be described as an embodiment with reference to the drawings.

FIG. 1 is an external perspective view of a recording / reproducing apparatus for a tape cassette with a radio receiving function (hereinafter, simply referred to as a tape recorder with a radio). The tape recorder with radio 1 records and reproduces an audio tape cassette having a size of about 10 cm × 6.5 cm. In addition, the tape recorder with radio 1 can receive stereo FM broadcasts, and based on the electric field strength of the FM broadcasts, a stereo local function of lowering the receiving sensitivity to demodulate and output a stereo output, and a demodulating without lowering the receiving sensitivity. A stereo DX function for performing stereo output and a monaural DX function for demodulating and outputting monaural without lowering the receiving sensitivity can be selected.

The tape recorder 1 with a radio has substantially the same size as the above-described audio tape cassette.
It is composed of a main body 2 and a lid 3. The main body 3 is provided with an operation input unit 4 provided with operation input buttons for performing operation inputs by a user, and tuning buttons 5a and 5b for receiving FM broadcasts.

The operation input unit 4 includes a reproduction button 6 for performing a reproduction operation, a stop button 7 for stopping a reproduction operation and the like, as operation input buttons for recording and reproduction of a tape cassette, and the like.
A fast forward button 8 for performing a fast forward operation and a rewind button 8 for performing a rewind operation are provided. The operation input unit 4 is not provided with a recording button or a pause button, but is provided, for example, on the front surface of the lid 3 (not shown).

The operation input unit 4 includes a menu button 11 for setting each function of the tape recorder 1 with a radio, a set button 12, and a liquid crystal display for displaying the setting of each function. (Hereinafter, simply referred to as an LCD) 13. In the tape recorder 1 with radio, the menu button 11 and the set button 1
By switching 2, the reception sensitivity of the radio function can be switched, and the stereo and monaural outputs can be switched. This menu button 11, set button 1
2 and the LCD 13 will be described later in detail.

Such a tape recorder with radio 1
The lid 3 is rotatably attached to the main body 2,
When the lid 2 is open, the tape cassette is loaded into a cassette loading section composed of a magnetic head, a reel shaft, a capstan shaft and the like. The tape recorder with radio 1 performs operations such as reproduction when an operation input such as the play button 6 is input while a tape cassette is loaded.

The tape recorder with radio 1 receives FM broadcasts by setting the tuning buttons 5a and 5b, the menu button 11 and the set button 12.

Next, the internal circuit of the tape recorder with radio 1 will be described. FIG. 2 is a block diagram of a main part of the tape recorder 1 with radio.

The tape recorder with radio 1 comprises an antenna 15 for receiving FM broadcasts, an FM playback unit 16 for playing back FM broadcasts received by the antenna 15, and a tape cassette recording and playback unit 20 for recording and playback of tape cassettes.
And the FM reproducing unit 16 and the recording / reproducing unit 2 of the tape cassette
And an output amplifier 21 for amplifying the output of 0. The tape recorder 1 with a radio includes an LCD 13, an FM
A system controller 10 for controlling the reproducing unit 16, the tape cassette recording / reproducing unit 20, and the output amplifier 21; and a key input circuit for inputting operation signals from the menu button 11 and the set button 12 and supplying an input signal of each button to the system controller 10. 14 is provided.

The tape cassette recording / reproducing section 20 performs recording / reproducing of the tape cassette based on operation inputs of the reproduction button 6 and the stop button 7 and supplies a stereo output to the output amplifier 21.

The antenna 15 receives a stereo FM broadcast broadcast from a broadcast station. In this FM broadcast, a stereo audio signal is broadcast. Also, the antenna 15
May be an audio signal of a television broadcast. The antenna 15 supplies the received FM broadcast reception signal to the FM reproduction unit 16.

The FM reproducing section 16 includes an attenuation circuit 17 and an FM
A demodulation circuit 18 and a stereo demodulation circuit 19 are provided.

The attenuation circuit 17 has an FM
A broadcast reception signal is supplied. The attenuation circuit 17 attenuates the FM broadcast reception signal by a certain level based on the operation input of the menu button 11 and the set button 12.
That is, in the tape recorder 1 with radio, the menu button 11 and the set button 12 are used to switch between stereo local where reception sensitivity is reduced and stereo DX and monaural DX which are normal reception sensitivity. When the stereo local is set, the attenuation circuit 17 attenuates the FM broadcast received signal attenuated by a certain level to the FM demodulation circuit 18.
To supply. When stereo DX or monaural DX is set, the attenuation circuit 17 supplies the FM broadcast reception signal to the FM demodulation circuit 18 without attenuating the signal.

The FM demodulation circuit 18 includes a high frequency amplification amplifier (RF amplifier), an oscillation circuit, a mixer, an intermediate frequency amplification amplifier (IF amplifier), an FM detection circuit (IF detector), and the like. It is carried out. The FM circuit demodulates the received signal of the FM broadcast and supplies an FM detection output to the stereo demodulation circuit 19.

Under the control of the system controller 10, the stereo demodulation circuit 19 switches between the L channel and the R channel stereo audio signals and monaural audio signals to output. The stereo audio signal and the monaural audio signal are switched according to the settings of the menu button 11 and the set button 12. The stereo demodulation circuit 19 supplies a stereo audio signal to the output amplifier 21 when stereo local or stereo DX is set, and outputs
When X is selected, a monaural audio signal is output from the amplifier 2
Feed to 1.

The output amplifier 21 amplifies the monaural or stereo supplied from the FM reproducing unit 16 and the tape cassette recording / reproducing unit 20 based on the switching control of the system controller 10, and supplies the amplified monaural or stereo to a speaker or an earphone.

The key input circuit 14 has a menu button 1
Operation input is performed from the 1 and set buttons 12, and an operation input signal of each button is supplied to the system controller 10.

The system controller 10 sets the functions of the FM reproducing unit 16 and the tape cassette recording / reproducing unit 20 based on the operation input of the menu button 11 and the set button 12 input through the key input circuit 14, and sets the function. The display of the contents of the function on the LCD 13 is controlled. The tape cassette recording / reproducing unit 20 or the F
The operation of the M playback unit 16 and the like is controlled.

Next, a method of switching the mode between the menu button 11 and the set button 12 and setting each function, and the display contents of the LCD 13 based on the switching of each function by the menu button 11 and the set button 12 will be described.

FIG. 3A is an enlarged view of a main part of the operation unit 4 for explaining display contents displayed on the LCD 13.

In the tape recorder 1 with radio, the mode when the system controller 10 performs each function setting is switched based on the operation input to the menu button 11. This mode includes a blank skip mode (BLS)
LIP), tape cassette playback direction switching mode (mode), and noise reduction mode (NR)
, Sound mode (SOUND), volume limiter mode (AVLS), and FM mode (FMMOD).
E). Blank skip mode (BLSLI
P) is a mode for setting whether to skip a silent portion of the tape cassette. The tape cassette playback direction switching mode (mode) is a mode for setting the tape cassette playback direction. The noise reduction mode (NR) is a mode for setting a noise reduction function when reproducing a tape cassette. The sound mode (SOUND) is a mode for setting an equalizing function when playing a tape cassette. The volume limiter mode (AVLS) is a mode for setting the peak value of the volume. FM mode (FMMODE)
Is a mode for setting monaural, stereo, and stereo local.

Each of these modes is operated by the menu button 11
Is switched by being pushed down. For more information,
As shown in FIG. 3B, each time the menu button 11 is pressed once, the mode is switched by one. The LCD 13
For example, a cursor 21 is displayed to indicate the currently selected mode. This cursor 21 indicates the current mode position by sequentially moving the position of each mode symbol of the input operation unit 4.

In the tape recorder 1 with the radio, in the mode selected by the menu button 11, the detailed function setting in each mode can be performed by the set button 12.

That is, the blank skip mode (BL
If you select “SLIP”, set button 1
2 sets whether to skip the blank portion of the tape cassette. When skipping a blank portion, for example, “ON” is displayed on the LCD 13. When the mode (mode) for switching the playback direction of the tape cassette is selected, the set button 12 is used to set the playback direction of the tape cassette. By setting the playback direction with the set button 12, an arrow indicating the playback direction is displayed on the LCD 13. When the noise reduction mode (NR) is selected, it is set by the set button 12 whether or not the recording / reproduction of the tape cassette is performed by applying the noise reduction function. When the noise reduction function is used, the type of the noise reduction function, for example, “B” or “C” is displayed on the LCD 13. When the sound mode (SOUND) is selected, the user can use the set button 12 to set, for example, whether or not to reproduce the bass sound with emphasis. When the volume limiter mode (AVLS) is selected, the set button 12 sets whether to limit the peak value of the volume. When setting the peak value of the volume, for example, a face mark or the like is displayed on the LCD 13. FM
Details of the mode will be described later.

That is, the mode to be the first layer is selected by the menu button 11, and the function setting of the second layer, which is the detailed setting of the function in the mode selected by the set button 12, is performed. Therefore, in the tape recorder 1 with radio, various types of function settings can be performed by setting the functions by dividing the hierarchy using the menu button 11 and the set button 12.

Next, the function setting when the FM mode is selected by the menu button 11 will be described with reference to FIG.

When the FM mode is selected,
A stereo local function that demodulates and outputs a stereo by lowering the receiving sensitivity of each function when receiving a stereo FM broadcast, a stereo DX function that demodulates and outputs a stereo without lowering the receiving sensitivity, and a demodulating without lowering the receiving sensitivity A monaural DX function for performing monaural output is set.

The functions of the stereo DX, monaural DX and stereo local are performed when the FM mode is selected by the menu button 11, that is, when the FM MODE is selected.
When the set button 12 is pressed when the cursor 21 is displayed at the city of the city, the switching is performed.

When stereo DX is set, FIG.
As shown in (a), only the cursor 21 is displayed on the LCD 13 and the others are not displayed. When the monaural DX is set, as shown in FIG.
, A MONO display 22 is displayed at the FMMODE position. Also, when stereo local is set, FIG.
As shown in (c), a LOCAL display 23 is displayed on the LCD 13 at the FMMODE position.

Each function of the FM mode displayed as described above is sequentially switched from stereo DX to monaural DX to stereo local when the set button 12 is pressed, and is switched again to stereo DX after stereo local. That is, when the set button 12 is sequentially pressed, each function is switched cyclically.

When each function of the FM mode is set by the menu button 11 and the set button 12, the system controller 10 causes the attenuation circuit 17 of the FM reproduction unit 16 to operate.
Then, the function setting of the stereo demodulation circuit 19 is performed.

Specifically, when the stereo DX is set, the FM broadcast reception signal is supplied to the FM demodulation circuit 18 without being attenuated by the attenuation circuit 17, and the stereo demodulation circuit 19 outputs a stereo audio signal. I do. When the monaural DX is set, the reception signal of the FM broadcast is supplied to the FM demodulation circuit 18 without being attenuated by the attenuation circuit 17, and the monaural audio signal is output from the stereo demodulation circuit 19. When the stereo local is set, the FM broadcast reception signal is attenuated by a fixed amount by the attenuation circuit 17 and supplied to the FM demodulation circuit 18, and the stereo demodulation circuit 19 outputs a stereo audio signal.

As described above, in the tape recorder 1 with radio, switching can be performed cyclically by setting each function of the stereo DX, monaural DX or stereo local with the menu button 11 and the set button 12. it can. In the tape recorder 1 with radio, the currently set function is displayed on one liquid crystal display unit 1.
3 can be displayed, and parts can be unified.
Also, by unifying parts in this way,
The board can be unified, and work efficiency is improved.

Further, since the switching is performed cyclically, the system controller 10 can execute the control of the output port for switching the receiving sensitivity and the port for switching between stereo and monaural with one program. Therefore, the algorithm of the control program can be unified.

In this embodiment, the broadcast to be received is described as FM broadcast. However, the broadcast system is not limited to FM broadcast, and may be, for example, AM broadcast.

[0048]

In the radio receiver according to the present invention, the mode is switched to the radio reception mode by the mode switching key, and the monaural function, the stereo function, and the stereo local function are set by the selection key. Accordingly, a monaural output signal, a stereo output signal, and a stereo output signal having a reduced reception sensitivity are output. As a result, the function of the radio receiver can be switched in a cycle. Further, since the switching is performed in a cycle, the control program of the control circuit can be simplified and executed.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a recording / reproducing apparatus for a tape cassette with a radio reception function to which the present invention is applied.

FIG. 2 is a block diagram of a main part of a recording / reproducing apparatus for a tape cassette with a radio receiving function to which the present invention is applied.

FIG. 3 is a diagram for explaining display contents at the time of mode switching.

FIG. 4 is a diagram for explaining display contents of a liquid crystal display unit when an FM mode is selected.

[Explanation of symbols]

1 tape recorder with radio, 10 system controller, 11 menu button, 12 set button,
13 liquid crystal display section, 15 antenna, 16 FM reproducing section, 17 attenuating circuit, 18 FM circuit, 19 stereo demodulating circuit, 20 tape cassette recording / reproducing section, 21 output amplifier

Claims (2)

[Claims] 1. A mode switching key for switching an operation mode, a setting key for setting a function in an operation mode switched by the mode switching key, a receiving antenna for receiving a stereo audio broadcast, and the stereo audio An attenuation circuit for attenuating the signal level of a broadcast reception signal; an audio signal demodulation circuit for demodulating the reception signal; and a stereo audio signal or monaural audio signal generated and output from the reception signal demodulated by the audio signal demodulation circuit. In the stereo demodulation circuit, in the switched radio reception mode, when the stereo function is set by the setting key, a stereo audio signal is output from the stereo demodulation circuit, and when the monaural function is set by the setting key, Output a monaural audio signal from the stereo demodulation circuit and press the setting key. And a control circuit for causing the audio signal demodulation circuit to demodulate a stereo audio broadcast whose signal level has been attenuated by the attenuating circuit and to output a stereo audio signal from the stereo demodulation circuit when the stereo local function is set. Receiving machine. 2. The radio receiver according to claim 1, wherein the audio signal demodulation circuit demodulates a frequency-modulated stereo audio broadcast reception signal.