JPS6051289B2 - Transmission control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a transmission control device that controls transmission by voice input in a one-way radio device or the like.

A conventional device of this type is shown in FIG.

In the figure, 1 is a microphone, 2 is an amplifier that amplifies the audio input signal from microphone 1, and 3 is an amplifier 2.
4 is a transmission control circuit that operates the transmitter 5 when the output of the rectifier 3 is equal to or higher than a predetermined threshold;
Reference numeral 5 represents a transmitter, and reference numeral 6 represents a timer circuit that continues the transmission activation of the transmission control circuit 4 for a certain period of time. Next, the operation will be explained.

When a voice enters the microphone 1, it is converted into an electrical signal, which is amplified and rectified by the amplifier 2 and rectifier 3 to become a DC signal sufficient to drive the transmission control circuit 4. For example, the transmission control circuit 4, such as a voltage application relay, When the DC input is equal to or greater than a predetermined threshold, audio input is detected and the transmitter 5 is placed in a transmitting state. Furthermore, although there is a pause in the voice, the transmission control circuit 4 continues to start transmitting for a certain period of time by providing a time constant to the time limit circuit 6, and the transmitter 5 maintains the transmitting state until the next voice comes in. . Furthermore, in order to prevent speech interruption, which is the biggest technical problem in voice-controlled transmission, devices have been developed in which the above-mentioned circuit is provided with a special function, such as a delay circuit that delays voice signal transmission.

Since the conventional transmission control device is configured as described above, there is an operating limit, that is, a threshold value for the input, and lowering this threshold value, that is, increasing the sensitivity, shortens the startup time due to the time constant at startup, This will reduce the occurrence of interruptions at the beginning of speech, but on the other hand, it will operate more sensitively with a small amount of voice input over a long period of time.
It had the drawback of emitting unnecessary radio waves.

In this case, although it is possible for the operator to restrict the voice control function by operating a switch, in practice it is cumbersome to perform manual operations each time there are many calls, and this is not a wise measure. This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the threshold value of the voice input required for the voice control is set in multiple stages, and when there is no voice input,
It will be in a low sensitivity state, and once the voice control function is activated, it will be in a high frequency state, and this state will continue even if the call is interrupted, and it will automatically switch to a lower sensitivity state after a certain period of time. The purpose of the present invention is to provide a transmission control device that provides the following functions. An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, the same reference numerals as in FIG. 1 indicate the same things, and 7 is a sensitivity switching circuit that has a plurality of input thresholds necessary for starting transmission of the transmission control circuit 4 and switches the sensitivity of the audio control operation. This sensitivity switching circuit 7 is inserted between the rectifier 3 and the transmission control circuit 4. Numeral 8 is a long-time time circuit to which the output of the sensitivity switching circuit 7 is input, similar to the time limit circuit 6, and this long-time time circuit 8 controls the sensitivity switching circuit 7 after a certain period of time has elapsed since the device started voice control operation. This is to switch the sensitivity to low sensitivity.

Next, the operation will be explained.

The sensitivity switching circuit 7 is normally in a low sensitivity state with a high threshold for audio input. Therefore, it does not operate sensitively to weak or instantaneous sounds, and is sufficiently stable against external noise. When an input necessary for voice input control, such as when talking into the microphone 1, that is, at a level exceeding the above-mentioned high threshold, is input, the amplifier 2 and rectifier 3 generate a DC signal sufficient to drive the transmission control circuit 4. is generated, and the transmitter 5 is brought into operation by the transmission control circuit 4. At this time, the sensitivity switching circuit 7 automatically switches the threshold value of the audio input required to maintain the audio control function to a low level, that is, to a state of high sensitivity. In addition, when the audio is interrupted, the time limit circuit 6 keeps the transmission control circuit 4 in the transmission activation state. At the same time, the long time limit circuit 8 also operates, and a longer time than the time limit circuit 6 has elapsed. The sensitivity switching circuit 7 is operated so that the sensitivity returns to the low frequency state before the start of the call.
This time can be adjusted to an appropriate value depending on the usage environment and operation mode. By doing this, in a state of high sensitivity, the biggest problem with voice transmission control can be solved. This reduces the problem of interruptions at the beginning of a conversation, makes full use of the voice control function during a series of calls, and reduces malfunctions due to noise due to low sensitivity during pauses in calls. In the above embodiment, a sensitivity switching circuit is provided on the input side of the transmission control circuit to switch the sensitivity at the DC signal stage, but the sensitivity can also be adjusted at other parts, such as the amplifier stage, and the audio input threshold Anything that is adjustable is within the scope of the present invention.

Furthermore, although the beginning of the conversation is relatively prone to interruptions at the beginning of the call, the interruptions at the beginning of the conversation are kept to a low level after the start of the call, and the practical effect is not significantly reduced throughout the entire duration of the call.
Furthermore, in order to temporarily compensate for the initial startup sensitivity, it is effective to manually set the sensitivity switching circuit to a high sensitivity state for a short period of time before starting a call. As described above, according to the present invention, the audio transmission control device has a plurality of input threshold values necessary for starting transmission, and a sensitivity switching circuit that enters a high-sensitivity state with the lower threshold value after starting transmission, and a sensitivity switching circuit for starting transmission. By providing a long-time time circuit that sets the sensitivity switching circuit to a low sensitivity state with the high threshold value mentioned above after a certain period of time has elapsed from As a result, the conventional problem of unnecessary transmissions interfering with lines can be solved, the field of use of voice control can be expanded, and the disadvantages of the one-way communication system can be easily and greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main structure of a conventional transmission control device, and FIG. 2 is a block diagram showing the main structure of a transmission control device according to an embodiment of the present invention. 4... Transmission control circuit, 5... Transmitter,
6...Time limit circuit, 7...Sensitivity switching circuit, 8...Long time time limit circuit.

Claims (1)

[Claims] 1. In a transmission control device equipped with a transmission control circuit that detects audio input and operates a transmitter, and a time limit circuit that continues the transmission activation of this transmission control circuit for a certain period of time, the threshold value of the input necessary for the transmission activation is set. There are multiple sensitivity switching circuits, which are in a low sensitivity state with a high threshold value before starting transmission and are in a high sensitivity state with a low threshold value after starting transmission, and a sensitivity switching circuit which is in a low sensitivity state with a high threshold value described above before starting transmission, and a sensitivity switching circuit which is in a high sensitivity state with a low threshold value after starting transmission, and after a time longer than the fixed time of the above time limit circuit has elapsed from the time of starting transmission. A transmission control device comprising: a long-time time circuit for switching a sensitivity switching circuit to a low sensitivity state with a high threshold value.