JPS5912840Y2 - display device - Google Patents

Description

[Detailed description of the invention] This invention is an FM stereo receiver with three FM detection outputs.
In addition to being able to check the balance of character characteristics extremely easily,
It is an object of the present invention to provide a display device in which the left and right audio levels can be checked extremely easily using the same group of light emitting elements by simply switching a switch.

In general, in an FM receiver, if it is not tuned correctly, the high part of one sideband will be cut off, resulting in decreased fidelity, increased distortion, increased noise, and poor stereo separation. Therefore, in order to listen to the broadcast correctly, it is necessary to tune in correctly.

However, in an FM receiver, it is difficult to find the correct tuning point by hearing because the volume of the speaker does not change even if there is a slight deviation from the tuning point.

However, the conventional method of indicating the tuning point is as follows: (4) A method of detecting the 10.7 Mz carrier from the middle of the intermediate frequency amplification stage.

(B) A type that is equipped with an intermediate wave amplification circuit especially for tuning, which causes the meter to swing.

0 A system in which the S-shaped characteristic of the frequency discriminator is directly indicated by a meter.

(D) Using a Schmitt trigger, the output of the frequency discriminator is displayed as a lamp.

There are methods such as 0, and it is difficult to achieve synchronization reliably with methods other than 0.

That is, in systems other than (C), when the antenna power level changes from a small input to a large input, complete tuning cannot be achieved and the point of minimum distortion does not match the maximum point of the tuning meter.

For this reason, systems other than the 0 type are used as a signal meter that indicates the magnitude of a signal rather than a tuning meter, and the two meters may be used together, with the center indicator type meter being used as the tuning meter.

In addition, with methods other than 0, it is necessary to match the meter deflection with the tuning point, which requires time to adjust, and also
Accurate tuning can be achieved by using a meter to directly indicate the S-shaped characteristic of the detection output, such as the method described above, but since the zero point of the meter must be read, considerable skill is required to read the perfect tuning point. That was difficult.

On the other hand, in an FM stereo receiver, it may be possible to add a function to display the left and right audio signal levels and adjust the sound pressure from the left and right speakers, but there is a problem that the addition of this function will increase the cost. there were.

The present invention eliminates the drawbacks of such conventional devices, and the present invention will be described below with reference to drawings of embodiments.

1 and 2 show an embodiment of the present invention, in which 1 is an FM tuner circuit consisting of a high frequency amplifier, a frequency converter, and a local oscillator, and 2 is an intermediate frequency converter circuit whose frequency has been converted by the FM tuner circuit 1. This is an intermediate frequency amplification circuit for amplifying frequency voltage, and a frequency discriminator 3 is connected to the final stage thereof.

4 is a differential amplifier for detecting the balance of the detection output from the frequency discriminator 3, and this differential amplifier 4 includes transistors Tr□ connected symmetrically as shown in FIG.

Tr2. Tr3. It is composed of Tr4 and operates as follows.

First, the output from the frequency discriminator 3 has an S-shaped characteristic depending on the frequency between its output terminals A and B as shown in FIG. 3A, and the point where VA-B becomes 0 is the optimum tuning point.

If the frequency shifts slightly upward from the optimal tuning point as shown by the arrow in Figure 3, the potential at point A will fall below the potential at point B, causing the differential amplifier circuit 4 to become unbalanced, as shown in Figures C and D. The potential at the point goes up and down as shown in Figure 3.

Therefore, the potential at point 0 rises from the potential at point D, transistor Tr1 is turned on, transistor Tr2 is turned off, and the potential at points E and F in Figure 2 increases as shown in Figure 3, 2 and E. However, the voltage at point F remains at OV.

Here, point E is connected to a lamp drive circuit 5 via a switch S, and this lamp drive circuit 5 increases the number of lamps lit in accordance with an increase in input voltage, so as the voltage at point E increases, Light emitting diode D1. D2. D3.
D4. D5 lights up.

On the other hand, point F is connected to lamp drive circuit 5' via switch S'.
Therefore, when the frequency shifts downward from the optimum tuning point, the other light emitting diode group D'1. D'2. D'3. D'4. Light up D'5 in sequence.

The light emitting diode group 11° 11' has one light emitting diode D1, D2, . D3. D4
．． D5, the other light emitting diode D'1°D'2. D'3
．． D'4. They are arranged in horizontal letters D'5, and when they are at the optimum tuning point, all the light emitting diodes turn off, and when they are detuned downward from the optimum tuning point, they turn off from the center of the element row to the right. The light-emitting diodes begin to light up, and conversely, when the tuning is upwardly detuned from the optimum tuning point, the light-emitting diodes light up from the center of the element array toward the left.

By configuring the tuning finger device in this way, it is possible to easily obtain the optimum tuning point in a short time depending on the lighting state of the light emitting element group. By arranging them appropriately, you can more intuitively find the optimal tuning point.

Next, 8 is a stereo multiplex demodulator, 9.9'
10° and 10' are left and right audio level detectors, respectively, and S and S'1 are switches that interlock with each other to switch between a tuning instruction and a left and right audio level instruction.

Then, the switch s1. When S'l is switched to the audio level detector 10.10', the output from the audio level detector 10.10' causes the lamp drive circuit 5,
5' is controlled and drives the light emitting diode groups 11, 11', the left and right audio levels can be visually checked very easily, and a lamp drive circuit and light emitting element group for this purpose can be separately provided. Since the switching is done by a switch, there are great advantages in terms of cost and parts space.

FIG. 4 shows another embodiment of the present invention, which differs from the one in FIG. This is achieved by adding a lamp drive circuit 7 and a light emitting diode D6 driven by the lamp drive circuit 7.

In this case, when there is an input signal to the intermediate frequency thickening film 2, the detector 6 detects this input signal and causes a DC detection current to flow through the transistor Tr5, turning the transistor Tr5 ON.

Therefore, the collector current of the transistor Tr5 flows to the light emitting diode D6, and the light emitting diode D6 emits light.

This light-emitting diode D6 is arranged at the center of the light-emitting diode group 11.11' arranged horizontally, and is lit during tuning. There is an advantage that the lighting of the diode D6 allows reliable visual identification.

FIG. 5 shows still another embodiment of the present invention, which differs from the one in FIG. 4 by manual switch S1. Switch circuits 12, 12' are provided in place of S2, and these switch circuits 12, 12' are configured to be switched by a sensor 14 provided on the tuning operation knob 13.

In other words, the switch circuits 12 and 12' are connected to the sensor 14 provided on the knob 13, and when a part of the human body touches the knob 13, the switch circuit 12 and 12' are The 0 point of the switch circuit 12' is electrically connected to the A point, and similarly, the 07 point of the switch circuit 12' is electrically connected to the N point.

When the human body leaves the knob 13, the 0 point of the switch circuit 12 returns to conduction with the B point, and the 07 point of the switch circuit 12' returns to conduction with the B' point.

Therefore, without providing any other switch circuit, the tuning indicating device operates only when the tuning is performed, and in other cases, it operates as the stereo audio signal level indicating device, so there is no need to perform troublesome switching operations. The instruction mode changes automatically, which is very convenient.

In this embodiment, a touch switch is used as the switch circuit 12, 12', but other switches may be provided in conjunction with the tuning knob, such as by pushing or pulling the tuning knob. The intended purpose can also be achieved by mechanical means of switching.

As described above, according to the present invention, there is provided a differential amplifier that detects the balance of the three-character characteristics of the FM detection output, a detector that receives a stereo audio signal as input and detects the left and right audio levels, and the detector or the two systems of light emitting element drive circuits controlled by the output signals of the differential amplifiers, two light emitting element groups including at least two or more light emitting elements controlled by the output signals of these light emitting element drive circuits, and the detection or switching means for selecting a signal path for the output signal from the differential amplifier to the two light emitting element drive circuits, and when the switching means is on the differential amplifier side, When the optimum tuning point is detuned in one direction, the light emitting element groups in one set operate sequentially according to the degree of detuning, and when the optimum tuning point is detuned in the other direction, the light emitting element groups in the other set operate sequentially according to the degree of detuning. It operates sequentially according to the degree and performs the synchronization instruction operation,
When the switching means is located on the detector side, the two light emitting element groups are configured to operate sequentially in accordance with the left and right audio levels to instruct the stereo audio signal level. You can visually confirm the stereo audio signal level indication.

In particular, when instructing left and right stereo audio signals, the number of light emitting elements that make up the two light emitting element groups changes depending on the level, so the level should be displayed in addition to the balance instruction. It has the advantage of being able to

In addition, it is possible to switch and use the drive circuit and light emitting element group without separately providing a drive circuit and a group of light emitting elements, which has a great cost advantage.
In addition, it requires only a small amount of storage space within the FM stereo receiver, so its practical value is extremely great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the display device of the present invention, FIG. 2 is a specific circuit connection diagram of the main parts of the device, FIG. 3 is an explanatory diagram of the operation of the device, and FIGS. 4 and 5 FIG. 2 is a block diagram showing another embodiment of the display device of the present invention. 2...Intermediate frequency amplifier, 3...Frequency discriminator, 4...Differential amplifier, 5.5', 7.
...Drive circuit, 6°10, 10'...Detector, 9,9'...Audio signal amplification section, 11,1
1'... Light emitting element group, D6... Light emitting element, 12.12'. SL, S2...Switching means.

Claims (6)

[Scope of utility model registration request] (1) A differential amplifier that detects the balance of the three-character characteristics of the FM detection output, a detector that receives a stereo audio signal as input and detects the left and right audio levels, and the output signal of the differential amplifier or the detector. Two systems of light emitting element drive circuits to be controlled, two sets of light emitting element groups including a plurality of light emitting elements controlled by output signals from these light emitting element drive circuits, and output from the differential amplifier or the detector. A switching means is provided for selecting a signal path for a signal to the two light emitting element drive circuits, and the two light emitting element groups are selected according to the magnitude of the output signal of the differential amplifier or the detector. A display device characterized in that the display device is configured to change the number of light-emitting elements of a plurality of light emitting elements. (2) A detector that detects a signal indicating that an input signal is being received from the FM intermediate frequency amplification stage, a drive circuit that is controlled by the output from this detector, and an output signal from this drive circuit. Utility model registration claim 1, comprising a controlled light emitting element, wherein the light emitting element includes a tuning indicator that operates in response to the received input signal.
Display device as described in section. (3) The switching means is configured electrically or mechanically, and when the tuning operation knob is not operated, the output from the detector for detecting the stereo audio signal level is input to the two light emitting element drive circuits. Claim 1 or 2 of the Utility Model Registration Claim characterized in that when the tuning operation knob is operated, the output from the differential amplifier is switched so that it is input to the two systems of light emitting element drive circuits. Display device as described in section. (4) The scope of the utility model registration claim, characterized in that the switching means is switched so that the output from the differential amplifier is forcibly input to the two systems of light emitting element drive circuits when the tuning operation knob is operated. The display device according to item 3. (5) In the two sets of light emitting element groups, the light emitting elements constituting them are arranged in a horizontal letter shape, and they are sequentially lit from the center outward in response to the output signal from the differential amplifier or detector. A display device according to claim 1 of the utility model registration claim, characterized in that the display device is configured to do so. (6) The display device according to claim 2, wherein the light emitting elements constituting the tuning indicator are arranged at the center of two groups of light emitting elements arranged in a horizontal character pattern.