JPS58194439A - Display circuit - Google Patents

Abstract

PURPOSE:To realize a synchronizing display during AM and FM monaural reception modes as well as an FM stereo display, by using a single display means with use of a multi-color light emitting element having different colors. CONSTITUTION:When the output of a terminal 1a exceeds a level set previously when an AM or FM monaural signal is received at a wave detecting circuit 1 of a receiving circuit I , transistors TRQ1 and Q2 of a synchronous display circuit IIare turned on to actuate a green light emitting diode D1 of a multi-color light emitting element IV. In this case, an FM stereo demodulating circuit 2 holds a terminal 2a at level H and then switches the terminal 2a to level L when it receives an FM stereo signal. Then a TRQ3 of a stereo display circuit III is turned on to actuate a red light emitting diode D'. In this case, a diode D2 conducts to set the anode of the diode D1 at a low potential. As a result, no current flows to the D1 with no emission of light. Thus it is possible to have plural displays with just a single display means. This decreases the number of component parts as well as the number of displays of a receiver.

Description

[Detailed description of the invention] This invention relates to the line display circuit.

Conventionally, in radio receivers with FM, there has been an example in which separate light-emitting diodes were used to display the dome display and the FM stereo display. At the end of this rounded stereo signal reception pattern, two LEDs for tuning display and stereo display will light up. However, such a display has the disadvantage that it increases the number of displays on the surface of the receiver and increases the number of parts, making it complicated.

Therefore, it is an object of the present invention to display AM
Tuning display and KF during reception and FM mono full reception
FM stereo display when receiving M stereo is displayed in different colors! An object of the present invention is to provide a display circuit that allows

The first of this invention! l! An example is shown in Figure @1. In other words, it shows an example of this display circuit company's FM-AM stereo radio, where ■ is the receiving circuit, and 1 is the IF (intermediate frequency).
An amplifier and a detection circuit supply a voltage proportional to the received signal to terminal IJIK. I is a tuning display circuit consisting of transistors Q□, Q2 and resistors R to R4. 2 is a multi-cube light emitting device (LED) consisting of first and second light emitting diodes 01a D'l that emit light of different colors. In these configurations, when an AM or FM monaural signal is received, the terminal 1a (D output of circuit I is set in advance and reaches a level higher than 9), transistor Q is turned on,
Since the rounding transistor Q2 is also turned on, the light emitting diode drawer lights up. 10B is a power supply.

On the other hand, in the receiving circuit 1, 2 is an FM stereo demodulation circuit, and its terminal 2a is set to a high level when receiving an FM stereo signal.
It is drawn out so that it changes to low ([, OW) level when a stereo signal is received.

■ is a stereo display circuit, which is composed of a transistor Q3 and a resistor R5eR6, and a light emitting diode "," is connected to its collector circuit. are connected in the direction shown in the diagram.

In the above configuration, when the AM front receives the FM monaural signal, the terminal 21 is at a high level, so the transistor Q3 of the stereo display circuit 1 is turned off, and the light emitting diode V
It doesn't light up, but when receiving FM stereo reconnaissance, the terminal'
1m becomes low level, the transistor Q3 turns on and lights up like a light emitting diode. Also, when the terminal 21 is at a low level, the switching diode D2 is turned on! +, Even when FM stereo is being received, the tuning display device turns on, but since the potential on the anode side of light emitting diode A is lowered, no current flows to the light emitting diode, and the light emitting diode stops emitting light. . As a result, for example, if the light emitting diode drawer is green and the light emitting diode 9 is red, the tuning display will be displayed in green, and the stereo
! 1 When receiving an audio signal, the green display changes to red and a stereo display is performed. It should be noted that in the case of FM stereo display, even if the synchronized display is not performed, the FM stereo display is sufficient for dormitory use as a display function.

In this way, a plurality of displays can be performed with a single display means, and the number of parts and the number of receivers displayed can be reduced.

A second embodiment of the invention is shown in FIG. That is, in place of the switching diode D2, this display circuit uses an input terminal of the tuned display circuit, ie, a titanium transistor Q.
A switching transistor ζ is connected between the base of □ and ground, and its base is connected to the collector side of the transistor Q3 in the FM stereo display circuit diagram via a base resistor R7.

As a result, when receiving an FM mono full signal and an AM borrowed signal, the switching transistor Q4 is turned off while the transistor Q3 is turned off.Therefore, in the tuned state, the transistors Q+Q2 are turned on and the light emitting diode (light-emitting diode) emits green light. do. On the other hand, when receiving an FM stereo signal, the transistor Q3 turns on and the switching transistor Q4 turns on, so the transistor Q does not turn on even if it is in tune, so the light emitting diode D does not turn on. The light emitting diode emits red light. The rest is the same as the 10th East Example.

As described above, the display circuit of the present invention includes a tuned display circuit,
FM stereo display circuit. By configuring the switching means and the multi-cuff light emitting element as described above, it is possible to display distinction and synchronization when receiving AM and FM mono full signals as well as when displaying KFiJFM stereo, and moreover, it can be displayed using a single display means. This has the effect of reducing the number of displays, making the surface of the ringing sound cleaner, and reducing the number of parts.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first embodiment of the invention, and FIG. 2 is a circuit diagram of a second embodiment.

Claims (1)

[Scope of Claims] (IJ) A receiving circuit, a multi-color light emitting element that displays a tuned state of this receiving circuit, a tuning display circuit for lighting the first light emitting element of the color light emitting element; and an FM stereo demodulation circuit OF of the receiving circuit.
A stereo display circuit detects the operating state when receiving the M stereo signal and lights up the light emitting element of the multi-cube light emitting element Ore 2, and when the stereo display circuit is on,
and a switching circuit for turning off the first light emitting element. (The 21111 switching circuit is a switching diode that is connected to the anode side of the light emitting element of 1ItI@1 and the connection terminal that becomes the /CCI U level when receiving FM stereo of the previous #73 FM stereo recovery i11 circuit. The display circuit according to claim (1). (The 31IIm distribution switching circuit detects the operating state of the stereo display circuit and turns on to lower the level of the input voltage of the front six tuning display circuits.) Range number (display circuit described in section H).