JPS6064583A - Tuning auxiliary device - Google Patents

Abstract

PURPOSE:To attain ease of tuning operation of a television receiver by detecting a carrier component of a video intermediate frequency signal and allowing a speaker to output sound in response to the tuning state. CONSTITUTION:After the video intermediate frequency from an intermediate frequency amplifier 34 is amplified while the carrier component only is selected by a resonance circuit comprising a capacitor 51 and a coil 52 set to be resonated to the frequency of the carrier component, then detected by a detection circuit comprising a capacitor 55, diodes 56, 57 and a capacitor 58. This output is fed to a voltage controlled oscillator 60 as a control voltage and an oscillated output having a frequency in response to the tuning state is extracted from its output terminal. After the level is adjusted by a variable resistor 61 for sound volume adjustment, the output is given to a speaker 40 via a low frequency amplifier circuit 39 and sound representing the tuning state is outputted from the speaker 40.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to (1) a tuning assist device for assisting the tuning operation of a television receiver.

(Constitution of Conventional Example and Its Problems) A tuning assist device in a conventional color television receiver has a configuration as shown in FIG.

In FIG. 1, a video intermediate frequency signal is supplied to one end of a coupling capacitor 1, and the other end is connected to ground and a power supply B through bias setting resistors 2 and 3f, respectively. It is connected to the base of the carrier wave amplification transoster 4. The emitter of the carrier amplification transistor 4 is grounded, and the collector is connected to the power source B via a coil 5 and a capacitor 6, which are connected in parallel with each other to form a resonant circuit. The intermediate Tanoff 0 of the coil 5 is connected to the anode of the diode 7. The cathode of this diode 7 is connected to the other end of a capacitor 8 whose one end is grounded and forms a detection circuit together with the diode 7, and then connected to the base of a transistor 1o via a resistor 9. The emitter of the transistor 1o is grounded via a resistor 11 and connected to the minus input terminal of the co/gulator 12, and the collector is connected to the power supply B via a resistor 13 and the plus input of the comparator 14. connected to the terminal. Note that the emitter and collector of the transistor 16 are connected to each other via the resistor 15. On the other hand, a horizontal flyback pulse of positive polarity is supplied to the base of the sawtooth wave generating transistor 16 via a resistor 17, its emitter is grounded, and its collector is connected to the power supply element B via a resistor 18. It is grounded via a capacitor 19, and further connected to the plus input terminal of the converter ξ regulator 12 and the minus input terminal of the converter ξ regulator 14. Each output terminal of comparators 12 and 14 is connected to an input terminal of AND gate 20, respectively. In addition, a green cathode drive transistor 2I, a red cant drive transistor 22
And the blue cut drive transistor 23 has a green base.

Red and blue video signals are supplied respectively,
The resistors 24, 25 and 2 are connected to each other, respectively.
6, and the respective collectors are connected to the power source B through resistors 27, 28 and 29, respectively, and are also connected to the green cathode, red cathode, and blue cathode of the cathode ray tube 30, respectively. and,
The output terminal of the AND key 1-20 is connected via a diode 31 to the base of a green cathode driving transistor 21.

Next, the operation of this embodiment will be explained. The video intermediate frequency signal applied to one end of the coupling capacitor 1 is amplified by the carrier amplification transistor 4, and the coil 5 and the capacitor selected to resonate at the frequency of the carrier component of the video intermediate frequency signal. A carrier wave component is extracted by a resonant circuit consisting of a diode 7 and a capacitor 8, and is detected by a detection circuit consisting of a diode 7 and a capacitor 8, and is extracted as a DC voltage, and the voltage is highest at the optimum tuning point. When this DC voltage is applied to the base of the transistor 10 through the resistor 9f, the emitter voltage a of the transistor 10 increases as the base voltage increases, and the collector voltage a decreases as the base voltage increases. On the other hand, the horizontal flyback signal applied to one end of the resistor 17 is connected to the sawtooth wave generating transistor 16 and the resistor 1.
8 and a capacitor J9, it is converted into a sawtooth voltage C. Then, the emitter voltage a1 of the transistor 10 and the glass input terminal are each input with a sawtooth wave voltage C to the negative input terminal of the comparator 12, and the collector voltage b1 of the transistor 10 is input to the positive input terminal of the comparator 14. The voltages C are inputted, and the output terminals of the comparators 12 and 14 output pulsed output voltages d and e as shown in FIG. Further, these output voltages d and e are inputted to an AND gate 20, and the output voltages d and e are inputted into the AND gate 20 to obtain the output voltages d and e as shown in FIG. A loop-like output voltage f is output from the AND gate 20. As is clear from FIG. 2, when the tuning state approaches the optimum tuning point and the emitter voltage a of the transistor IO increases and the collector voltage decreases, the AND signal
The pulse width of the output voltage f of the gate 20 becomes narrower. In this way, an AND key whose wave width changes depending on the tuning state.
The output voltage f of the cant 20 is supplied to the base of a green cant drive transformer 210 via a diode 31, mixed with a green video signal, and input to the cathode ray tube 30. Here, the output voltage f of the AND gate 20 is synchronized with horizontal scanning and is a signal signal, so it is displayed on the screen of the cathode ray tube 30 as a vertical green band with a width corresponding to the signal width. It is shown together with footage from the television broadcast.

Therefore, the width of this green band changes depending on the tuning state, and becomes the narrowest at the optimal tuning point.

However, in the above conventional example, the user only needs to pay attention to the green band projected on the screen and adjust the synchronization state, but the image of the TV Noyon broadcast is projected in the background of the green band. Therefore, in reality, it is necessary to perform the tuning operation while visually checking both the green band and the background image, which requires a complicated operation.

Also, depending on the brightness of the location where the TV receiver is installed, the green band projected on the screen may be difficult to see because the screen may shine, or it may be difficult to see changes in the width of the green band when moving away from the television receiver. Therefore, synchronization operations were sometimes difficult.

(Object of the invention) The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and
By audibly displaying changes in the tuning state, the user can detect the optimal tuning point from both visual and auditory perspectives, and the tuning assist device allows reliable tuning operations even when the screen is difficult to see. It provides:

(Structure of the Invention) In order to achieve the above object, the present invention extracts a carrier wave component of an optical intermediate frequency signal, detects it, converts it into a DC voltage that changes according to the tuning state, and converts this DC voltage The voltage-controlled oscillator is controlled by the voltage-controlled oscillator, and the frequency changes according to the tuning state output from the voltage-controlled oscillator, and the oscillation output that is maximum or minimum at the optimum tuning point is output to the audio circuit of the television receiver or other sounding body. A sound having a pitch corresponding to the tuning state is output from the television receiver's speakers or other sounding body.

(Explanation of Examples) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a diagram showing the configuration of a color television solenoid image receiver 4at equipped with an embodiment of the present invention. In Figure 3,
32 is an antenna, 33 is a nayuna, 34 is an intermediate frequency amplifier circuit, 35 is a detection circuit, 36 is a video amplifier circuit, 37 is an audio intermediate frequency amplifier circuit, 38 is a detection circuit, 39 is a low frequency amplifier circuit, 40 is a speaker, 41 is a color reproduction circuit, 42 is a synchronization circuit, 43 is a deflection circuit, and 44 is a cathode ray tube.These are the main parts that make up a color television receiver, and all color television receivers have them. Since this is generally well known, a detailed explanation thereof will be omitted and only one embodiment of the present invention will be described.

In FIG. 3, one end of a coupling capacitor 45 is connected to the output end of the intermediate frequency amplification circuit 34, and the other end is grounded via a bias setting resistor 46 and a bias setting resistor 47. After being connected to the power supply element B via , it is connected to the base of the carrier wave amplification transistor 48 . The emitter of the carrier wave amplification transistor 48 is grounded via a resistor 49 and a capacitor 50, and the collector is grounded via a capacitor 51 and a coil 52.
are connected in parallel to each other, and then connected to the power source B via a resistor 53 and grounded via a capacitor 54. The collector of the carrier wave amplifying transistor 48 is also connected to the cathode of a diode 56 and the anode of a diode 57 via a capacitor 55. The anode of the diode 56 is grounded, and the cathode of the diode 57 has one end grounded. The other end of the capacitor 58 is connected to the other end of the capacitor 58.

Note that the capacitor 55, diodes 56, 57, and capacitor 58 constitute a detection circuit, the output end of which is connected to the i1+II control terminal of the voltage controlled oscillator R560. It is connected to the. The output terminal of the voltage controlled oscillator 60 has a collector connected to the power source B, and an emitter connected to a variable resistor 61 for volume adjustment and grounded, and connected to the base of a transistor 62 constituting a tough follower circuit. A sliding terminal of a variable resistor 61 from which the output of the 16727107 circuit is taken out is connected to the input end of the low frequency amplifier circuit 39 via a coupling capacitor 63.

Here, the voltage controlled oscillator 60 is configured as follows. The negative input terminal of the converter resistor 64 is used as a control terminal of the voltage controlled oscillator 60, and its output terminal is connected to the voltage i1Q+B via the resistor gy6E, and also to the CMO3/NAND gate 64. 1-6
It is connected to one input terminal of 6. CMO3-NA
The output terminal of the ND metro 6 is connected to a differential circuit with one end of a capacitor 67 grounded via a resistor 68, a resistor 69, and a capacitor 1 of a diode 70 for negative voltage absorption whose anode is grounded. CMo3
The other input terminal of the CMo8-NAND card is connected to the power supply 1B, and the output terminal of the CMo8-NAND card is connected to one input terminal of the CMo8-NAND card. It is connected to the other input terminal of the controller 6, and is connected via a resistor 72 to the other end of a resistor 73 whose one end is connected to a power supply 1B, and then to the base of a switching transistor 74. The switching transistor 74 has an emitter connected to the power supply 1B, a collector grounded via a capacitor 75, and grounded via resistors 76 and 77 in sequence, and further between the resistors 76 and 77. Kon・
It is connected to the glass input terminal of the regulator 64. An oscillation output is taken out from the collector terminal of the switching transistor 74.

Next, the operation of this embodiment will be explained. Note that this embodiment has the configuration shown in FIG. 3 during the tuning operation, and when the tuning operation is not performed, the intermediate frequency amplification circuit 34 shown in FIG.
The thread path that enters the low frequency amplification circuit 39 from the output terminal of the carrier wave amplifying transistor 48 and the voltage controlled oscillator 60 etc. is open, and only after entering the tuning operation state does the above thread path become as shown in the figure. close. Then, the video intermediate frequency signal from the intermediate frequency amplification circuit 34 is supplied to the pace of the run/meta 48 for carrier wave amplification via the cuff O-ring capacitor 45, so that it resonates at the frequency of the carrier wave component of the video intermediate frequency signal. After only the carrier wave component is selected and amplified by a resonant circuit consisting of a capacitor 51 and a coil 52 set to
6.57 and a detection circuit consisting of a capacitor 58, the wave is detected and converted into a DC voltage according to the tuning state. This DC voltage is supplied as a control voltage to the voltage controlled oscillator 60, and an oscillation output with a frequency according to the tuning state is taken out from its output terminal. After the level is adjusted by the variable resistor 61, the signal is supplied to the low frequency amplification circuit 39. Then, a sound indicating the tuned state is emitted from the audio output speaker 40 of the color television receiver.

Here, the operation of the voltage controlled oscillator 6o will be explained with reference to FIGS. 4(a) and 4(b). 4(a) and (b) respectively show the signal waveforms of the main parts when the control voltage is relatively low and when the control voltage is relatively high, and g is the input voltage waveform of the positive input terminal of the comparator 64. ,h
is the input voltage waveform of the negative input terminal of the comparator 64, that is, the control voltage waveform; 1 is the output voltage waveform of the comparator 64; J is the output voltage waveform of CMo8/NAND Ketro 6; k is CMo3-NAND One input voltage waveform of key door 1, t is the threshold level of CMo8 NAND key door 1, m iJ: CMo8 N
The output voltage waveform of AND key 1.71, n is the collector voltage waveform of the switching transistor 74.

First, when the output voltage m of the CMo8-NAND'r+- door 1 is at a high level, the switching transistor 74 is in an off state, the voltage of the capacitor 75 is discharged through the resistors 76 and 77, and the switching transistor 74 is in an off state.
4 collector voltage n and comparator 64. When the input voltage g at the positive input terminal of the comparator 64 becomes lower than the input voltage h at the negative input terminal, that is, the control voltage, the output voltage l of the comparator 64 becomes low level. At that moment, the output voltage J of the CMo8-NAND Ketro 6 becomes a high level, and this output voltage J is differentiated by a differentiator circuit consisting of a capacitor 67 and a resistor 68.
CM as a high-level input voltage.
It is supplied to one input terminal of the o3 NAND gate 1, and its output voltage m becomes low level. At this point, the switching transistor 74 turns on, its collector voltage n increases, and the capacitor 75
is rapidly charged, and the output voltage 1 of the comparator 64 immediately becomes high level. However, at this time 17) C
Mo3-NAND Ke”-Door] One input t Pressure k
f h 7r Differential = Since the Lus level is at a high level, the output voltage m of CMo5/NAND gate 1 remains at a low level, and therefore, CMo8/NAND
The output voltage J of the Dket9-Toro6 also remains at a high level.

When CMO8-NAND 'y''-door 1 (D) decreases to level tK-l, the output voltage m of CMO8-NAND gate 71 becomes high level, and the output voltage of cMos/NAND gate 71 becomes high level. j becomes low level, the switching transistor 74 is turned off, and the Abi capacitor 75 is turned off.
begins to discharge, and the collector voltage n of the switching transistor 74 begins to fall. In this way, the level of the collector voltage □ of the switching transistor 74 changes to the level of the capacitor 7.
The collector voltage n of the switching transistor 74 is taken out as the oscillation output of the voltage controlled oscillator 60. Further, the frequency of this oscillation output is determined by the control voltage supplied to the negative input terminal of the comparator 64 as the input voltage, as is clear from FIGS. 4(a) and 4(b). That is, C.M.O.
When the output voltage mi of the 8-NAND (7) is at the high level, the switching transistor 74 is turned off, the capacitor 75 is discharged, and the input voltage g of the input terminal of the comparator 64 gradually decreases. When the level of the control voltage, which is the input voltage at the negative input terminal of the comparator 64, is high as shown in FIG. Low level 9, Figure 4 (a
), the discharge time of the capacitor 75 is shorter than in the case where the level of the control voltage is low, so the frequency of the oscillation output taken out from the collector of the switching transistor 74 becomes high. Further, the control voltage is a DC voltage obtained by extracting, detecting and converting the carrier wave component of the video intermediate frequency signal, and its level changes depending on the tuning state, reaching a maximum at the optimum tuning point. Therefore, the frequency of the oscillation output of the voltage controlled oscillator 60 also changes according to the tuning state by the control 1 voltage described above, and becomes maximum at the optimal tuning point. Therefore, the timbre of the sound generated from the speaker 40 changes depending on the tuning state and becomes the highest sound at the optimal tuning point, so that the user can audibly detect the optimal tuning point.

In the above embodiment, the oscillation output of the voltage controlled oscillator 6o is supplied to the low frequency amplifier circuit 39 to generate a sound indicating the tuning state from the audio output speaker 40 of the color television receiver. The television receiver may be provided with another sounding body, and this sounding body may generate a sound indicating the tuning state. In the above embodiment, the sound indicating the tuning state is the highest at the optimal tuning point, but the sound may be the lowest at the optimal tuning point.

(Effects of the Invention) As explained below, the present invention extracts the carrier wave component of a video intermediate frequency signal, detects it, detects a DC voltage that changes in accordance with the tuning state, and performs voltage control using this DC voltage. Controlling an oscillator to change the frequency of its oscillation output so that it becomes maximum or minimum at the optimal tuning point, and outputting this oscillation output as sound from a speaker for audio output of a television receiver or other sounding body. This allows the user to visually check the actual television broadcast image on the screen and audibly detect the optimal tuning point during tuning operations, making the tuning operation easier and improving the television reception. Even if the screen is difficult to see because the place where the machine is installed is bright, the tuning state can be reliably adjusted to the optimum tuning point.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional tuning auxiliary device, FIG. 2 is a signal waveform diagram of the main parts of FIG. 1, and FIG. 3 is a diagram of a color television receiver equipped with an embodiment of the present invention. The diagrams illustrating the configuration, FIGS. 4(a) and 4(b), are the voltage control generator shown in FIG.
FIG. 5 is a signal waveform diagram of the main parts of the dragonfly when the control voltage is low and when the control voltage is high. 48 - Carrier wave amplification transistor, 60 Voltage controlled oscillator, 64... Comparator, 66.71... CMO
8-NAND+l”=74 Switching transformer 7
Star. Patent Applicant: Matsushita Electric Industrial Co., Ltd. Agent: Hisashi Hoshino Figure 4 (a) →Rep. Ku\S-kari\Ding-kari\

Claims (1)

[Claims] means for extracting a carrier wave component of a video intermediate frequency signal using a resonant circuit, detecting it and converting it into a DC voltage according to a tuning state; a voltage controlled oscillator whose oscillation frequency changes according to the DC voltage; and a voltage controlled oscillator whose oscillation frequency changes according to the DC voltage. and means for supplying the oscillation output from the oscillator to the audio circuit of the television receiver (8) or other sounding body, the frequency of the oscillation output of the voltage controlled oscillator changing in accordance with the tuning state during tuning operation. The tuning assist device is characterized in that the frequency of the oscillation output reaches a maximum or minimum at an optimum tuning point, and a sound corresponding to the frequency of the oscillation output is emitted from a speaker for audio output of the television receiver or the other sounding body.