JPS6336755Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to a display device that displays the operating status of a noise blanker circuit.

2. Description of the Related Art

Generally, a radio device such as a transceiver has a built-in noise blanker circuit for removing pulse noise. This noise blanker circuit is
A noise detection circuit equipped with an operation level setting circuit,
The noise detection circuit detects the input signal and detects the noise adjusted to a desired level by the operation level setting circuit. The gate control circuit outputs a gate control signal when the switch is turned on and the noise detection signal exceeds the threshold level, and the noise blanker gate outputs a gate control signal when the switch is turned on and the noise detection signal exceeds the threshold level. It is configured to be switched to a non-conducting state to attenuate or cut off the signal when the signal is turned off. Therefore, when the switch is on, the noise blanker circuit is activated, and when a noise detection signal exceeding a predetermined threshold level is input to the gate control circuit, it is regarded as noise input, and the input signal is The signal is removed by being attenuated or blocked. Even when the switch is on, if the noise detection signal does not exceed the predetermined threshold level, the input signal is passed through as is. When the switch is always on, when an input signal with low noise but high level is input and the noise detection signal exceeds the threshold level, the noise blanker circuit operates and distortion occurs in the demodulated signal. When pulse noise is not generated, the switch is turned off to put the noise blanker circuit into a non-operating state. The actuation level can be set to a desired level by the actuation level setting circuit.

[Issue to be solved]

However, for example, if noise is mixed in the input signal and the noise disappears when the switch is turned on, the noise may have been removed from the input signal by the operation of the noise blanker circuit, or the noise itself may have disappeared. It is not possible to determine whether That is, when the switch is turned on, it is impossible to determine whether noise is occurring or not.In other words, even when the switch is turned on, it is not possible to determine whether the noise blanker circuit is operating to remove noise. Therefore, there is a problem in that even though the noise has actually decreased, the switch remains on, and it is not possible to accurately judge when to turn it off even though the quality of the demodulated signal remains poor. In addition, the noise blanker circuit is equipped with a level setting circuit so that the operating level can be adjusted to prevent activation by signals other than noise, but as mentioned above, the operating state of the noise blanker circuit can be determined. Therefore, it is difficult to adjust the operating level quickly and appropriately, and there is also the problem that the noise blanker circuit operates due to signals other than noise.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a noise detection circuit including a noise detection circuit equipped with an operation level setting circuit, a gate control circuit in which a predetermined threshold level is set, a noise blanker gate, and a switch. In the blanker circuit, the noise detection circuit detects an input signal and outputs a noise detection signal adjusted to a desired level by the operation level setting circuit, and the gate control circuit detects the input signal when the switch is turned on and outputs a noise detection signal adjusted to a desired level by the operation level setting circuit. A gate control signal is output when the noise detection signal exceeds the threshold level, and the noise blanker gate is switched to a non-conducting state to attenuate or block the signal when the gate control signal is input. In the noise blanker circuit configured as such, by inputting the gate control signal or a signal interlocked with the gate control signal that appears when the noise blanker gate is switched to a non-conducting state by the gate control signal. The present invention has adopted a method that includes a detection circuit that detects the non-conducting state of the noise blanker gate and outputs a noise blanker activation signal, and a display circuit that is driven by the noise blanker activation signal.

[Effect]

In the noise blanker circuit display device according to the present invention, when the noise detection signal output from the noise detection circuit due to the signal input exceeds a predetermined threshold level and the switch is on, the gate control circuit A gate control signal is output, and the gate control signal switches the noise blanker gate to a non-conducting state to attenuate or block the input signal. Therefore, when pulsed noise whose level is higher than that of the target signal is generally input, the noise detection signal output from the noise detection circuit exceeds the threshold level, so the pulsed noise is removed. It is. At this time, the detection circuit detects the gate control signal,
Alternatively, by inputting a signal that is linked to the gate control signal that appears when the noise blanker gate is switched to a non-conducting state by the gate control signal, the non-conducting state of the noise blanker gate is detected and noise is generated. Since a blanker activation signal is output and a display circuit is driven by the noise blanker activation signal, the operating state of the noise blanker gate can be visually or audibly confirmed by the display circuit. Therefore, if it is no longer necessary to operate the noise blanker gate, by turning off the switch, the gate control signal will not be output from the gate control circuit even if the noise detection signal is input, and the noise blanker gate will not be output. The gate is conductive and allows signals to pass through. Further, when the noise blanker circuit is activated by a signal other than noise, the noise blanker circuit is operated properly by changing the operation level using the operation level setting circuit while checking the display on the display circuit. be able to.

【Example】

An embodiment of this invention will be explained in detail below based on the drawings. In Figure 1, the part NB surrounded by a broken line is a noise blanker circuit with a general circuit configuration, and
1 and G2 are noise blanker gates made of diodes, and D is the noise blanker gate G1 and G2.
diode to control, NA is a noise amplifier. ND is a noise detector for noise detection, is equipped with an operation level setter VR, and outputs a noise detection signal Sn adjusted to a desired operation level. Q is a transistor as a gate control circuit, and outputs a gate control signal Sg when the input noise detection signal Sn exceeds the threshold level at which this transistor is turned on and the switch SW is turned on. do. Then, the noise blanker gates G1 and G2 become non-conductive due to the gate control signal Sg, thereby attenuating or blocking the input signal Si. Reference numeral 1 indicates a detection circuit, for example, a NAND circuit connected in series to the connection point A of the noise blanker gates G1 and G2, 2 a signal conversion circuit, and 3 a display circuit. First, to explain the noise blanker circuit NB, normally, a reverse bias is applied from the DC power supply +B to the diode D through the resistors R1, R2 and the capacitor C, and the diode D is turned off and both noise blanker gates G1 and G2 are turned on. In other words, it is in a conductive state. The input signal Si input to the input terminal I is amplified by the noise amplifier NA, detected by the noise detector ND, and outputs the noise detection signal Sn adjusted to the desired operation level by the operation level setter VR. , when the level of this noise detection signal Sn does not exceed the predetermined threshold level, the transistor Q is not turned on and the gate control signal is
without outputting Sg, the noise blanker gate G1,
G2 is in an on state, that is, a conductive state. Therefore, the input signal Si is output from the input terminal I to the output terminal O via both noise blanker gates G2 and G1. However, when the input signal Si, which is considered to be noise exceeding a predetermined signal level, is input to the input terminal I, the signal component is amplified by the noise amplifier NA and detected and extracted by the noise detector ND, resulting in the desired operating level. Outputs the adjusted noise detection signal Sn, and if the switch is on, the transistor Q
The base potential of the transistor Q rises, the transistor Q becomes conductive, and the gate control signal Sg is output. The diode D is controlled by this gate control signal Sg.
transitions to the on state, and both noise blanker gates G
The potential at the connection point A between 1 and G2 decreases, and current no longer flows through the noise blanker gates G1 and G2.
Since it becomes a high impedance and becomes non-conductive, cutting off the input signal Si, the input signal Si from the input terminal I will no longer be output from the output terminal O only when the signal considered to be noise is input. , the signal considered to be noise can be removed. Here, when the switch SW is turned off, the emitter circuit of the transistor Q is cut off, so even if the level-adjusted noise detection signal Sn output from the noise detector ND exceeds the threshold level, the gate control signal Sg remains unchanged. There is no output, and the noise blanker gates G1 and G2 are in a conductive state,
Do not attenuate or block input signal Si. The detection circuit 1 includes both noise blanker gates G
A NAND circuit was used to detect the drop in potential at the connection point A of 1 and G2. If a decrease in the potential of the connection point A that is linked to the gate control signal Sg is detected, the noise blanker gates G1 and G2 are activated.
Since we can know the non-conducting state of
The NAND circuit is designed to output the noise blanker activation signal Sb only when the potential at the connection point A drops. There are various possible circuit configurations with such functions other than NAND circuits, but
Since the period of pulse noise is very short, any circuit configuration having the above function can be applied as long as attention is paid to the speed of response. In addition, in order for the detection circuit 1 to know the non-conducting state of the noise blanker gates G1 and G2, it is necessary to use not only the connection point A but also a gate control signal Sg that causes a potential drop at this connection point A.
Of course, it is also possible to use an equivalent signal appearing at the collector of the transistor Q or other parts. In any case, it is sufficient if the non-conducting state of the noise blanker gates G1 and G2 can be known directly or indirectly. In the case of pulsed noise, since the period of the noise is extremely short, the signal conversion circuit 2 generates the noise blanker activation signal Sb so that it can be recognized reliably.
is converted into a predetermined display signal, and the display circuit 3 is driven by the display signal. For example, if an unstable multivibrator is used as the signal conversion circuit 2 to convert it into a display signal that continues for a predetermined period of time, and a drive circuit that blinks an LED is used as the display circuit 3,
Even extremely short noises can be displayed by blinking the LED for a predetermined period of time, making them reliably visible. Furthermore, if a buzzer drive circuit or a voice synthesis circuit is added as the display circuit 3, more reliable display will be achieved. As explained above, the noise blanker circuit NB
Since the non-conducting state of the noise blanker gates G1 and G2 is detected and displayed, the switch
You can know exactly when to turn off the SW,
The noise blanker circuit can be utilized extremely effectively. In addition, the operation level for operating the noise blanker circuit is set by the operation level setting device VR to the display circuit 3.
By adjusting while looking at the screen, you can accurately and easily adjust the level to the appropriate level, and prevent the noise blanker circuit NB from operating due to signals other than noise. If NB is activated,
Since a warning is given by the display on the display circuit 3, there is an advantage that the operation level can be corrected to an appropriate level by adjusting the operation level setter VR.

【effect】

In the noise blanker circuit display device according to the present invention, when a signal deemed to be noise exceeding a predetermined level is input, the noise blanker gate becomes non-conductive, and the detection circuit detects that the noise blanker gate is non-conductive. By detecting the conduction state and driving the display circuit accordingly, the operating state of the noise blanker circuit including the noise blanker gate can be visually or audibly confirmed, so that the noise blanker circuit is activated. Thus, it is possible to reliably and easily determine whether there is no noise or whether the noise input itself has disappeared. Therefore, it is possible to accurately know when to turn off the switch, and by turning off the switch based on the display on the display circuit, the noise blanker circuit can be utilized extremely effectively. Furthermore, by adjusting the operating level of the noise blanker circuit while looking at the display on the display circuit, it is possible to accurately and easily adjust the operating level to an appropriate level, and to prevent the noise blanker circuit from operating due to signals other than noise. Moreover, even if the noise blanker circuit is activated by a signal other than noise, a warning is displayed on the display circuit, so that the operational level of the noise blanker circuit can be corrected to an appropriate level.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of a display device using a noise blanker circuit of this invention. 1...Detection circuit, 3...Display circuit, G1, G2
...Noise blanker gate, NA...Noise amplifier, NB...Noise blanker circuit, ND...Noise detector, Q...Transistor (gate control circuit), Sb...Noise blanker activation signal, Sg...Gate control signal , Si...input signal, Sn...noise detection signal, SW...switch, VR...operation level setter.

Claims (1)

[Claims for Utility Model Registration] A noise blanker circuit comprising a noise detection circuit equipped with an operation level setting circuit, a gate control circuit in which a predetermined threshold level is set, a noise blanker gate, and a switch. The noise detection circuit detects the input signal and outputs a noise detection signal adjusted to a desired level by the operation level setting circuit, and the gate control circuit outputs a noise detection signal when the switch is turned on and the noise detection signal is adjusted to a desired level by the operation level setting circuit. outputs a gate control signal when the noise blanker gate exceeds the threshold level, and the noise blanker gate is configured to be switched to a non-conducting state to attenuate or block the signal when the gate control signal is input. In the noise blanker circuit, the noise blanker gate is controlled by inputting the gate control signal or a signal that is linked to the gate control signal that appears when the noise blanker gate is switched to a non-conducting state by the gate control signal. 1. A display device for a noise blanker circuit, comprising: a detection circuit that detects a non-conducting state and outputs a noise blanker activation signal; and a display circuit that is driven by the noise blanker activation signal.