JPS6233387Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a tuner, and particularly to improvements in its tuning and voltage reduction indicating device.

Conventionally, a so-called signal meter method, a tuning meter method, or the like has been used as a tuning instruction device in an FM tuner or the like.

However, in any case, such conventional tuning instructing devices have complicated configurations, and cannot organically and effectively provide instructions for tuning and detuning.

Therefore, this idea was made in view of the above points. When detuning, the multivibrator is set to an oscillating state and the two display elements flash alternately, and when tuning, the multivibrator is set to an oscillating state and one of the display elements is set to a non-oscillating state. By lighting only the elements continuously and setting the conditions to ensure that the multivibrator starts when the power switch is turned on, the configuration can be simplified and the instruction format for tuning and detuning can be organically controlled without malfunctions. It is an object of the present invention to provide an extremely good tuning and voltage reduction indicating device that is both effective and effective.

An embodiment of this invention will be described in detail below with reference to the drawings.

That is, in FIG. 1, 11 is, for example, FM/
This is a tuner circuit that can be used for both AM and the like, and in this case, by performing tuning processing on the received radio waves captured by the antenna ANT, a direct current output of V is generated from the tuning instruction output terminal T at the time of tuning. The tuning instruction output terminal T of this tuner circuit 11 is connected to the tuning instruction side contact TI of the battery voltage instruction/tuning instruction switching switch _S1 .

Further, the common contact c of the changeover switch _S1 is connected to the base of the transistor _Q1 , and the battery voltage indicating side contact BC is the midpoint between the resistors _R1 and _R2 connected in series between the power supply line A and the ground. It is connected to the.

Here, the emitter of the transistor _Q1 is grounded, and its collector is connected to the power supply line B via the resistor _R3 , and is also connected to the base of the switching transistor _Q2 constituting the multivibrator M. This transistor Q ₂ has its base grounded via a capacitor C ₁ , its emitter, which is its current path, is grounded via a light emitting diode D ₁ serving as the first display element, and its collector connected to a capacitor C ₂ It is grounded via R4 and connected to power supply line A via resistor _R4 .

Furthermore, the switching transistor _Q3 , which also constitutes the multivibrator M, has its emitter, which is its operating current path, connected to ground via the light emitting diode _D2 , which serves as the second display element, and its base connected to the power supply via the resistor _R5 . It is connected to line A, and its collector is grounded via capacitor C ₃ and also connected to power supply line A via resistor R ₆ .

Here, capacitors _C4 and _C5 are respectively connected between the collectors of transistors _Q3 and _Q1 and between the collector of transistor _Q2 and the base of transistor _Q3 .

In the above description, power line A is connected to battery power source E via power switch _S2 , and power line B is connected to power line A via ripple filter LF. This ripple filter LF may be replaced with a constant voltage circuit or an RC filter, and its output is connected to the power supply terminal (not shown) of the tuner circuit 11 in addition to the above power line B. It is.

Next, in the above configuration, first, select the changeover switch.
The operation will be explained when _S1 is set as the tuning instruction side contact TI. In this case, it is assumed that the power switch _S2 has been turned on in advance (the same applies to each of the following cases).

Therefore, a DC output voltage of V is not output from the tuning instruction output terminal T of the tuner circuit 11, and O
(V) When the output is detuned, the transistor _Q1 for controlling the multivibrator M is cut off. Therefore, the multivibrator M consisting of a pair of switching transistors Q ₂ and Q ₃ enters an oscillation state, causing the light emitting diodes D ₁ and D ₂ , which serve as the first and second display elements, to blink alternately. This indicates that it is in an out-of-tune state.

On the other hand, the tuning instruction output terminal T of the tuner circuit 11
During tuning in which a DC output voltage of V from is output, the control transistor _Q1 described above is turned on, so
Transistor _Q2 is cut off and transistor _Q3 is turned on. That is, in this case, the multivibrator M stops oscillating, and only the light emitting diode _D2 serving as the second display element is continuously lit, thereby indicating that it is in the tuned state.

In other words, the above-mentioned display when detuning and when tuning is such that the first and second display elements blink alternately when detuning, and only the second display element lights up continuously when tuning. Since it is a wink indicator system, the indication form can be made organic and effective.

Next, selector switch S ₁ switches to the battery voltage indication side contact.
The case where BC is set will be explained. First, when the voltage of the battery power source E is high enough, the resistor
Since sufficient base current is supplied to the control transistor Q ₁ through R ₁ to turn it on, the multivibrator M stops oscillating in the same way as when tuning the tuning instruction side contact TI described above. A light emitting diode D ₂ becomes the second display element.
This indicates that the battery power source E is at the normal voltage by causing only the battery power source E to light up continuously.

On the other hand, when the voltage of the battery power supply E decreases, the above-mentioned control transistor Q ₁ is cut off, and the multivibrator M enters the oscillation state as in the case when the tuning instruction side contact TI is detuned. By alternately blinking the light emitting diodes D ₁ and D ₂ which become the first and second display elements,
Indicates that the battery power source E is in a state where the voltage is lower than the normal voltage.

Since this battery power instruction form also uses a wink indicator system like the above-mentioned tuning instruction form, it can be done organically and effectively.

Next, a description will be given of how the above-mentioned tuning instruction/battery voltage indicating device is designed to prevent malfunctions and adverse effects on other circuits.

First, multivibrator M turns on power switch S ₂
One point is that the conditions are set so that it can always be activated when it is turned on. In other words, if the transistors Q ₂ and Q ₃ happen to be in balanced conditions when the power switch S ₂ is turned on, the multivibrator M is prevented from being unable to start, and the conditions are set so that the multivibrator M can always be started. It is. Specifically, this is achieved by actively changing the balance between both transistors Q ₂ and Q ₃ by supplying the base bias of one transistor Q ₂ from the power supply line B through the ripple filter LF. be done.

In other words, in this case, the base bias of the other transistor _Q3 is given from the power supply line A that does not pass through the ripple filter LF, so as a result, the input of the ripple filter LF (or a constant voltage circuit or RC filter is also possible) is applied. Due to the voltage difference and voltage rise time difference between the outputs, both transistors
The operating conditions of Q ₂ and Q ₃ will be unbalanced, and the conditions are set so that the multivibrator M (in this case, the so-called unstable type) can be started without fail even when the power switch S ₂ is turned on. It is. This makes it possible to prevent malfunctions when the power switch _S2 is turned on.

Next, the switching noise in the oscillation operation of the multivibrator M is caused by the AM of the tuner circuit 11.
The advantage is that it prevents interference from entering the band tuning section and causing interference to other circuits. In other words, this is achieved by capacitors C ₂ and C ₃ inserted between the collectors of transistors Q ₂ and Q ₃ and ground.
This is caused by bypassing the switching noise component to ground.

In addition, in this case, it is virtually impossible for the switching noise generated by turning on and off of the transistor _Q1 that controls the multivibrator M to cause disturbances such as jumping into the AM band tuning section as in the above case. the transistor
Capacitor inserted between collector of Q ₁ and ground
This is prevented in the same way as described above in _C1 .

Figure 2 shows an implementation example when the above embodiment is applied to a cassette tape recorder with a radio receiver for both _FM and _AM . This is a light emitting diode for indicating battery power (voltage).

In the above embodiment, the changeover switch _S1 can be used for both tuning instructions and battery power (voltage) instructions, making it extremely convenient.

In addition, in the above embodiment, the first and second
Since the light emitting diodes D ₁ and D ₂ (or lamps, etc. are also acceptable) that serve as display elements are connected to the emitters of the transistors Q ₂ and Q ₃ , each cathode (or negative) side is common, reducing the number of wires to one. This has the advantage of reducing the number of books.

It goes without saying that this invention is not limited to the embodiments described above and illustrated, and that various modifications and applications can be made without departing from the gist of this invention.

Therefore, as detailed above, according to this invention, when detuning, the multivibrator is placed in an oscillating state and the two display elements are alternately blinked, and when tuning, the multivibrator is placed in an oscillating state and only one display element is turned on and off. If you want to set the multivibrator to a condition that allows it to light up continuously and to start the multivibrator reliably when the power switch is turned on, by using a wink indicator method, the configuration can be simplified and the timing of tuning and detuning can be easily controlled without causing malfunction. It becomes possible to provide an extremely good tuning and voltage reduction indicating device that is improved so that the indicating form can be made organically and effectively.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing an embodiment of the tuning and voltage reduction indicating device according to the invention, and FIG. 2 is an external perspective view showing an example of implementation of the same embodiment. 11... tuner circuit, S ₁ ... changeover switch,
M...Multivibrator, _Q1 , _Q3 ...Transistor, _C1 to _C5 ...Capacitor, _R1 to _R6 ...Resistor, _D1 to _D2 ...Light emitting diode, E...Battery power supply, LF ... Ripple filter, S ₂ ... Power switch.

Claims (1)

[Scope of utility model registration request] A multivibrator having a pair of switching transistors, and a first display element and a second display element inserted into each operating current path of the pair of switching transistors; A control transistor that controls the multivibrator to an oscillation state or an oscillation stop state by controlling a switching transistor to a switching operation enable state and a switching operation stop state; voltage dividing means for setting a specified voltage level for a transistor to switch the multivibrator from an oscillation stopped state to an oscillating state; a first state in which the output of the voltage dividing means is guided to the control transistor; and a first state generated from a tuner circuit. a second state in which a tuning instruction output is guided to the control transistor, and when the switch is in the first state,
When the output voltage level of the voltage dividing means is equal to or higher than the specified voltage level, only one of the first and second display elements is turned on continuously, and when the output voltage level of the voltage dividing means is equal to or lower than the specified voltage level. When the first and second display elements are alternately blinked, and the switch is in the second state, the first
and blinking the second display element alternately when detuned,
A tuning and voltage reduction indicating device characterized in that it is configured so that only one side lights up during tuning.