JPS5840686Y2 - TV remote control receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a remote control receiver for television.

In a remote control receiver equipped with a noise gate circuit, the noise gate operates due to signal reflection or interference from the transmitter, causing malfunctions such as blackout.

Therefore, in order to prevent this, a portion of the selector must be rendered insensitive immediately after receiving the desired signal.

This idea uses a noise gate circuit to quickly turn off the noise gate after receiving the desired signal to prevent malfunctions caused by reflection and interference, and also uses the same circuit to form a positive feedback circuit to generate intermittent oscillation. A pulse signal is obtained, and the controlled circuit is automatically advanced by this pulse signal.

Hereinafter, one embodiment of this invention will be described in detail based on the drawings.

In the drawings, reference numeral 1 denotes, for example, a ceramic microphone that receives a control signal (ultrasonic wave) supplied from a transmitter and converts it into a predetermined electric signal.

Here, the ultrasonic signal supplied from the transmitter means a control signal for, for example, sequential selection of channels, power ON/OFF, volume adjustment, etc.

Reference numeral 2 denotes a human-powered signal amplifier to which the output signal of the microphone 1 is supplied as an input, and is composed of, for example, four transistor amplification stages of CR coupling, and is designed to sufficiently amplify the minute input signal supplied. ing.

The amplified output of the input signal amplifier 2 is supplied to the selector section 4 via the transformer 3.

The selector section 4 stops at 44 and ±(power ON/
It consists of four parallel tuned circuits: 40 (volume up), 40 (volume down, power 0FF), and 38.5 K (channel switching), and outputs to the corresponding tuned circuit for each frequency signal input. are sorted and taken out.

These four types of signals are individually amplified by four columns of one-stage amplification, and then supplied to the load.

Q1 to Q4 are transistors for this purpose.

Further, reference numeral 5 denotes a noise gate composed of a noise amplification transistor Q5, a noise detection transistor Q6, and a noise gate drive transistor Q7.

The noise amplifying transistor Q5 is connected to the microphone 1.
A low frequency component (for example, a noise component due to a telephone ring or a metal fricative sound) included in the electrical signal (near 40 KHz) that is supplied is amplified and is supplied to the noise detection transistor Q6.

As a result, under normal conditions when no noise signal is supplied, O
The noise detection transistor Q6 and the noise gate drive transistor Q7, which are biased to the FF state, are both turned on, and the output of this noise gate circuit turns off the switching transistor Q8, which is connected to the common emitter of each transistor. become.

That is, under normal conditions, the switching transistor Q
8 is the transistor Q6 of the noise gate 5. Q7 is OF
Since it is F, the ON state is maintained, and the transistors Q1~
Q4 is operated at each signal frequency, but for low frequency components (noise) caused by, for example, a telephone ring, transistors Q6. When Q7 is turned on, it is turned off and circuit operation is interrupted.

However, the ultrasonic signal supplied to the microphone 1 is supplied as two signals that are different in phase and time due to reflection or interference from a wall or the like.

As a result, chattering occurs in the receiver, and malfunctions of the circuit itself (interference phenomenon due to the function of the noise gate) occur.

Therefore, in this invention, a transistor Q is provided, and the base side of this transistor Q1 is connected to the collector of the transistor Q9 via a time constant circuit formed by a resistor R1 and a capacitor C, and another time constant circuit ( Transistor Q1o via resistor R3 and capacitor C3)
, and the collector side thereof is connected to the base of the transistor Q6 via a time constant circuit formed by a resistor R2 and a capacitor C2.

Therefore, for example, when a signal with a frequency of 38.5 KHz (channel switching) is received, the reception of this signal first turns on transistor Q4, lowering its collector voltage, and causing the collector voltage of transistor Q to rise rapidly. do.

This output voltage is supplied to the base of the transistor Qll with a delay of a time constant τ1 caused by the resistor R1 and the capacitor C1, and makes the transistor Q1□ conductive.

As a result, the base of the transistor Q6 is grounded through the resistor R2, so the base voltage of the transistor Q6 decreases, and the transistor Q6 becomes conductive.
7 to turn off the switching transistor Q8.

As a result, the collector voltage of transistor Q4 increases and transistor Q9 is turned on again, so its collector voltage decreases and transistor Q□1 is turned off.

However, the rise in the base voltage of transistor Q6 is delayed by a time constant τ2 due to resistor R2 and capacitor C2.

Thereafter, the normal operating state is resumed, and if the 38.5 KHz signal is still present at this time, the above-described operation is repeated.

Each time the collector voltage of transistor Q6 rises, a pulse signal is output to RF, so the channel automatically advances.The volume down and OFF circuits operate in exactly the same way. The time constant of the base of transistor Qll is set larger than in the previous case.

This invention, as explained above, - After the operation is completed,
If it does not operate no matter what signal is supplied for a certain period of time, and if a continuous signal is supplied after a certain period of time, it will perform one more operation and become insensitive again, and if you continue to press the button on the transmitter, it will automatically turn off. The operation is configured to proceed as follows.

Therefore, according to this invention, the noise gate circuit can be turned off immediately after receiving the desired signal, and the reflection and
Malfunctions due to interference can be reliably prevented.

In addition, operations such as channel switching can be performed using intermittent pulses.
Since the process can proceed automatically, the product quality is improved.

[Brief explanation of drawings]

The drawing is an electrical circuit diagram of one embodiment of this invention. 1...Microphone, 2...Input signal amplifier, 3...Transformer, 4...Part of selector, 5...Noise gate circuit , Q1~Q
ll...Transistor, R1-R3...
・Resistance, C1 to C3...Capacitor.

Claims (1)

[Scope of utility model registration request] An input signal amplification section that amplifies the input signal corresponding to the ultrasonic signal supplied from the transmitter, and the input signal supplied from this input signal amplification section is divided into required frequencies and the tuned output is supplied to the load. a noise gate circuit that blocks circuit operation of the selector portion when a noise signal is supplied from the input signal amplification portion; and a predetermined input signal is supplied to the selector portion from the input signal amplification portion. A television remote control receiver comprising a positive feedback circuit that turns off the noise gate circuit with a predetermined time constant when the noise gate circuit is supplied.