JPH0342759Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Field of the Invention> The present invention relates to an audio data transmission device that includes a transmitter that transmits audio data and a receiver that receives audio data from the transmitter.

<Prior art and its problems> Conventionally, the receiving side automatically detects that audio data has started to be transmitted from the transmitting side, and the receiving side starts receiving and drives the recording means to record the audio data. There is an audio data transmission device called. This detection of the start of transmission on the receiving side is performed by determining that the transmission of audio data has started if the level of the input signal is above a certain level, but noise on the transmission line is detected as the start of transmission. There were problems such as erroneous judgments, malfunctions, and wasting the recording medium of the recording means.

<Purpose of the invention> The present invention has been made in view of the above-mentioned points, and its purpose is to eliminate the malfunction of reception start on the receiving side.

<Configuration and Effects of the Invention> In order to achieve the above-mentioned purpose, the present invention includes a start signal forming means for forming a start signal, a first timer for measuring a predetermined time, and a first timer for measuring a predetermined time on the transmitting side. Comparing a correspondingly preset level with the level of the input signal, and when the level is equal to or higher than the preset level, the signal is determined to be audio data and a drive signal is provided to the start signal forming means and the first timer. and when the input of audio data is started, the audio data is given to the comparator and the start signal is transmitted, and when the predetermined time has elapsed, the audio data is transmitted based on the output of the first timer. The receiving side is provided with a recording means for recording the received signal, a second timer for measuring a predetermined time, and a switching means for detecting a start signal transmitted from the transmitting side and switching the second timer. a start signal detection means for supplying a drive signal; and a start signal detection means for supplying a reception signal to the start signal detection means when a signal is received, and a reception signal for supplying a reception signal to the recording means based on the output of the second timer when a predetermined time has elapsed; A switching means is provided.

Therefore, according to the present invention, at the start of audio data transmission, a start signal is transmitted for a predetermined period of time, and after the reception side detects the start signal, the received audio data is stored in the recording means after a predetermined period of time has elapsed. Since the information is recorded, it is possible to eliminate the malfunction of reception start on the receiving side due to noise in the transmission line as in the conventional case.

<Description of Embodiments> Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. The audio data transmission device of this embodiment is
It includes a transmitting side 1 that transmits audio data, and a receiving side 2 that receives audio data from the transmitting side.

The transmitting side 1 basically includes an oscillator 3 as a start signal forming means that forms a start signal to be sent at the start of transmission, a first timer 4 that measures a predetermined time (10 mS in this embodiment), and an audio A preset level L1 (shown in FIG. 2) corresponding to the data is compared with the level of the input signal, and when the level is equal to or higher than the preset level L1, it is determined that the data is audio data, and the oscillator 3 and the 1
a first comparator 5 that provides a drive signal to the timer 4; when input of audio data is started, provides audio data to the first comparator 5 and transmits a start signal;
First and second analog switches 6 and 7 are provided as switching means for transmitting audio data based on the output of the first timer 4 when the predetermined time has elapsed.

The start signal is a high frequency (in this example
3KHz) and is selected for signals that are within the high-level audio band. This is to shorten the detection time of the start signal on the receiving side 2, and to make it easier to take the level difference with the audio data so that the audio data and the start signal can be easily distinguished. This is to avoid the need to widen the band for transmitting the start signal. The first timer 4 is turned on after a predetermined period of time has elapsed after receiving the drive signal from the first comparator 5, and remains on until the reset signal from the third timer 8 is provided.
Keep it ON. This predetermined time is selected to be a time that does not affect the transmission of audio data and allows the reception side to detect the start signal. In this example, 10ms is chosen as described above. 1st
The comparator 5 connects the microphone 9 to the amplifier 10,
The level of the signal input via the first analog switch 6 is compared with a preset level L1 corresponding to the audio data, and if the level is equal to or higher than the preset level L1, the audio data is input. For example, a drive signal is given to the oscillator 3 and the first timer 4, and a reset signal is given to the third timer 8.

The first analog switch 6 has individual contacts 6a, 6
b and a common contact 6c, and the connection is switched based on the output of the first timer 4. When the first timer 4 is ON, the common contact 6c and the individual contact 6b are connected, and the first timer 4 is turned on.
When it is OFF, the common contact 6c and the individual contacts 6a are connected. 2nd analog switch 7
has individual contacts 7a, 7b and a common contact 7c, and like the first analog switch 6, the connection is switched based on the output of the first timer 4. When the first timer 4 is ON, the common contact 7c and the individual contact 7b are connected, and when the first timer 4 is OFF, the common contact 7c and the individual contact 7a are connected. Second comparator 11
gives a preset signal to the third timer 8 when the level of the input signal is lower than a predetermined level L1. The third timer 8 provides a reset signal to the first timer 4 and resets the first timer 4 when the preset signal is not provided for a certain period of time T seconds after the preset signal is provided.
Turn off. This fixed time T is selected to be a sufficient time for determining that the transmission of audio data has ended.

The receiving side 2 basically includes a recording means 12 that records the received signal on a magnetic tape or the like, a second timer 13 that measures a predetermined time (10 mS in this embodiment),
a start signal detection means 14 which detects a start signal transmitted from the transmitting side 1 and provides a drive signal to the second timer 13; and when a signal is received, provides a reception signal to the start signal detection means 14;
When a predetermined period of time, ie, 10 mS, has elapsed, the recording means 12
and a third analog switch 15 as a switching means for providing a received signal.

The start signal detection means 14 detects a band corresponding to the start signal among the received signals provided via the third analog switch 15, which is 3KHz in this embodiment.
The level of the signal from this filter circuit 16 is compared with the level L2 (shown in the second diagram) set corresponding to the start signal, and the level of the signal from this filter circuit 16 is compared with the level L2 (shown in the second diagram), which is equal to or higher than the set level L2. and a third comparator 17 that sometimes provides a drive signal to the second timer 13 as a start signal. The second timer 13 operates for a predetermined period of time, that is, 10 mS after the drive signal from the third comparator 17 is applied.
It is then turned ON and continues to be ON until a reset signal from the fourth timer 18 is given.

The third analog switch 15 has an individual contact 15
a, 15b and a common contact 15c, and the connection is switched based on the output of the second timer 13. Second
When timer 13 is ON, common contact 1
5c and the individual contact 15b are connected and the second timer 13 is OFF, the common contact 15c
and the individual contact 15a are connected. 4th comparator 1
9, when the level of the input signal is lower than a predetermined level L1, the fourth timer 18 provides a preset signal. The fourth timer 18 provides a reset signal to the second timer 13 when no preset signal is provided for a certain period of time T seconds after the preset signal is provided.

Next, the operation of the audio data transmission device configured as described above will be explained. Before inputting audio data to the microphone 9, the first timer 4 is OFF.
Correspondingly, in the first analog switch 6, the common contact 6c and the individual contacts 6a are connected.
In the second analog switch 7, a common contact 7c and an individual contact 7a are connected. Further, at this time, the second timer 13 is also turned off, and correspondingly, in the third analog switch 15, the common contact 15c and the individual contact 15a are connected.

From the microphone 9 to the time t shown in FIG.
When audio data is input at step 1, the audio data is provided to the first comparator 5 via the amplifier 10 and the first analog switch 6. The first comparator 5 compares the level of the audio data with a preset level L1 shown in FIG. The indicated drive signal is applied to the oscillator 3 and the first timer 4. As a result, the oscillator 3 outputs a 3KHz start signal, and the first timer 4 starts driving and turns on 10 mS after time t1 as shown in FIG. 2C. By this,
From transmitter 1, 10mS via transmission line 20
During this time, a start signal is transmitted as shown in FIG. 2E.

Start of audio data input, that is, from time t1
After 10 mS has elapsed, the first timer 4 turns ON as shown in FIG.
The connection will switch between. By this, Figure 2 E
The audio data from the microphone 9 will be transmitted as shown in FIG.

The second comparator 11 provides a preset signal to the third timer 8 when the level of the audio data provided via the first analog switch 6 is lower than a preset level L1. The third timer 8 is
If the preset signal is not applied for a certain period of time T seconds after the preset signal is applied, it is assumed that the data transmission has been completed and is turned on as shown in FIG. 2D to give a reset signal to the first timer 4. As a result, when the transmission of audio data is completed, the first timer 4 is turned off as shown in FIG. 2C, and in response, the first and second analog switches 6 and 7 are Return to the state shown.

On the other hand, on the receiving side 2, before the audio data is input to the microphone 9, the second timer 13 is turned off, and the third analog switch 1 is turned off in response to this.
5, the common contact 15c and the individual contacts 15a are connected. When audio data is input from the microphone 9 at time t1 shown in FIG. 2 and a start signal is transmitted, it is applied to the start signal detection means 14 via the third analog switch 15. The start signal that has passed through the filter circuit 16 is compared with a preset level shown in FIG.
When this is the case, a drive signal is given to the second timer 13 as a start signal as shown in FIG. 2F. In this example, the start signal is
As mentioned above, since it is 3KHz, it can be clearly distinguished from noise of about 10KHz.

The second timer 13 receives the drive signal for 10mS.
Turns ON after the elapsed time. When this second timer 13 turns on, the third analog switch 15
Then, the connection is switched between the common contact 15c and the individual contact 15b, and as a result, only the received signal excluding the start signal transmitted for 10 mS is stored in the recording means 12 as shown in FIG. 2G. will be recorded. In this embodiment, the first timer 4
Since both the predetermined time and the predetermined time of the second timer 13 are equal to 10 mS, the recording means 12 records only the received signal corresponding to the audio data without wasting the magnetic tape.

In this way, in the present invention, a start signal is transmitted for a predetermined period of time when audio data transmission starts, and after the receiving side detects the start signal,
Since the received audio data is recorded in the recording means after a predetermined period of time has elapsed, it is possible to eliminate the malfunction of reception start on the receiving side due to noise in the transmission line as in the prior art.

[Brief explanation of the drawing]

1 is a block diagram of an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the audio data transmission device shown in FIG. 1, and FIG. Figure 2B is the output waveform of the first comparator 5, Figure 2C is the output waveform of the first timer 4, Figure 2D is the output waveform of the third timer 8, and Figure 2E is the output waveform of the third timer 8. Output waveform, FIG. 2F is the output waveform of the third comparator 17, FIG. 2G is the recording means 1
The input waveforms to 2 are shown respectively. 1... Transmission side, 2... Receiving side, 3... Oscillator (start signal forming means), 4, 13... 1st, 2nd timer, 6, 7, 15... 1st, 2nd, 3rd analog switch (switching means), 14...start signal detection means, 12...recording means.

Claims (1)

[Claims for Utility Model Registration] (1) A transmitting side that transmits audio data and a receiving side that receives audio data from the transmitting side, and the transmitting side includes a start signal forming device that generates a start signal. a first timer for measuring a predetermined time; and a first timer that measures a predetermined time; compares the level of the input signal with a preset level corresponding to the audio data, and when the level of the input signal is equal to or higher than the preset level, the audio data a comparator for supplying a drive signal to the start signal forming means and the first timer; and when the input of audio data is started, the comparator is supplied with audio data to transmit the start signal; A switching means is provided for transmitting audio data based on the output of the first timer when the time has elapsed, and the receiving side is provided with a recording means for recording the received signal and a second timer for measuring a predetermined time. a start signal detection means for detecting a start signal transmitted from the transmitting side and giving a drive signal to the second timer; and when a signal is received, a reception signal is given to the start signal detection means, and a predetermined time has elapsed. An audio data transmission device characterized in that it further comprises switching means for providing a received signal to the recording means, sometimes based on the output of the second timer. (2) The audio data transmission device according to claim 1, wherein the start signal has a high frequency included in the audio band and is a high level signal. (3) The audio data transmission device according to claim 1 or 2, wherein the predetermined time is equal to the predetermined time. (4) The start signal detection means includes a filter circuit that passes only signals in a band corresponding to the start signal, and a comparator that compares the level of the input signal with a level set corresponding to the start signal. An audio data transmission device according to claim 1, 2, or 3 of the utility model registration claim, characterized in that the device includes the following.