JPH0115920B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a handwriting transmission device that can simultaneously transmit narrow spectrum signals such as handwriting transmission signals without impairing the clarity of voice calls over telephone lines or the like.

Conventionally, when various types of handwritten signals are transmitted over general telephone lines, it is common to separate them spatially or temporally from the voice channel and transmit only the handwritten signals. In this case, it is not possible to ask questions or explain the contents of the handwritten signal transmission, and after the handwritten signal transmission is completed,
There was the inconvenience of having to switch back to the telephone line and then ask questions or explain things again.

In addition, if you want to transmit a telephone signal and a handwritten signal simultaneously, you can cut out a part of the telephone signal band and transmit the handwritten signal to this part. Transmission quality deteriorates. In this case, since the energy component of the telephone signal is small, other simultaneous transmission methods such as data transmission have conventionally used the upper band of the telephone signal, but in general telephone lines, the upper and lower limits of the transmission band are used. However, there are no guarantees regarding amplitude distortion, group delay distortion, etc., and when simultaneously transmitting telephone signals, etc. and handwritten signals using such bands, there may be a problem with the transmission quality of the handwritten signals. The problem was that there was no guarantee whatsoever.

The present invention uses a general telephone line, inserts a handwritten signal into a band with good transmission quality, and allows the voice call and the handwritten signal to have no influence on each other.
Simultaneous transmission has the remarkable effect of omitting a switching procedure and a dedicated line for transmitting handwritten signals.

Embodiments of the apparatus of the present invention will be described in detail below with reference to the accompanying drawings. However, the drawings are for illustrative purposes only, and are not intended to be limiting.
It goes without saying that various modifications may be made without departing from the spirit of the invention.

FIG. 1 is a circuit diagram showing one embodiment of the present invention. 1 is a general telephone line for voice, 2 is a telephone terminal,
3 is a handwriting vertical position signal input terminal for the sending end, 4 is a handwriting horizontal position signal input terminal for the sending end, 5 is a vertical position signal oscillation circuit whose oscillation frequency changes depending on the input from the input terminal 3, and 6 is a vertical position signal oscillation circuit. a horizontal position signal oscillation circuit whose oscillation frequency changes depending on the input from the input terminal 4;
7 is a mixing circuit that mixes the oscillation signals of oscillation circuits 5 and 6; 8 is a superimposition circuit that superimposes the output of mixing circuit 7 on the signal input from telephone terminal 2; and 9 is a signal transmitted over general audio line 1. 10 is a band filter that extracts a vertical position signal from the superimposed signal distributed by distribution circuit 9; 11 is a band filter that extracts a horizontal position signal from the superimposed signal distributed by distribution circuit 9; A PLL (Phase Looked Loop) oscillation circuit outputs only a frequency signal with an opposite phase to the frequency signal output from the band filter 10, and a PLL (Phase Looked Loop) oscillation circuit 13 outputs only a frequency signal with an opposite phase to the frequency signal output from the band filter 11.
The PLL oscillation circuit 14 is an AGC (automatic gain control) circuit controlled by the output of the bandpass filter 10. Note that the PLL oscillation circuit has a function of matching the phase of the frequency signal delayed by the bandpass filter with the phase of the handwritten signal included in the superimposed signal outputted by the AGC 14, and a function of inverting the phase-matched signal. 15 is a mixing circuit that operates the output signals from the PLL oscillation circuits 12 and 13 without affecting the spectrum; 16 is a mixing circuit that adds the signal from the mixing circuit 15 to the superimposed signal output from the AGC 14 to cancel and transmit the handwritten signal. 17 is a cancel circuit that outputs only the signal; 17 is a detection circuit that has a detection output function according to changes in the oscillation frequency output from the PLL oscillation circuit 12 and generates a handwritten vertical position signal corresponding to the input terminal 3; 18 is a PLL A detection circuit 19 has a detection output function according to changes in the oscillation frequency output from the oscillation circuit 13 and generates a handwritten horizontal position signal corresponding to the input terminal 4, and a detection circuit 19 outputs only the transmission signal input from the terminal 2. an output terminal of the cancel circuit 16;
20 is a terminal that outputs only the signal generated by the detection circuit 17 corresponding to the handwritten vertical position signal inputted to terminal 3, and 21 is a terminal outputting only the signal generated by the detection circuit 18 corresponding to the handwritten horizontal position signal inputted to terminal 4. This terminal outputs only the input signal.

Next, the operation of the above circuit will be explained. First, as shown in FIG. 2, the transmission signal 31 is input from the terminal 2, passes through the superimposition circuit 8, the telephone line 1, the distribution circuit 9, the AGC circuit 14, and the cancel circuit 16, and then reaches the terminal 19. The handwritten vertical position signal 321 inputted to the terminal 3 is converted by the oscillation circuit 5 into a frequency signal 322 within the general telephone line transmission band. Similarly, handwritten horizontal position signal 331 input to terminal 4
is converted into a frequency signal 332 by the oscillation circuit 6.
However, the frequency signals 322 and 332 have frequencies that can be separated by a filter, etc., and have amplitude characteristics,
Select a location near the center of the telephone line transmission band with good phase characteristics. The frequency signals 322 and 332 are mixed in a mixing circuit 7, and then sent to a superimposing circuit 8 and a terminal 2.
The signal is superimposed on the input transmission signal 31 and transmitted to the line 1. This superimposed signal is transmitted to the distribution circuit 9 on the receiving side.
and filtered by bandpass filters 10 and 11. When the handwriting transmission vertical signal 323 that has passed through the bandpass filter 10 is applied to the PLL oscillator 12, a signal whose phase is advanced by the phase delayed by the bandpass filter 10 and whose phase is inverted is transmitted to the output of the PLL oscillator 12. It appears as a position signal 324.
Similarly, when the handwritten transmission horizontal signal 333 that has passed through the bandpass filter 11 is applied to the PLL oscillator 13, a signal whose phase is advanced by the phase delayed by the bandpass filter 11 and whose phase is inverted is sent to the output of the PLL oscillator 13. This appears as a horizontal position signal 334. The handwritten vertical position signal 324 and the handwritten horizontal position signal 334 are mixed in the mixing circuit 15 and input to the cancel circuit 16 . On the other hand, from distribution circuit 9 to AGC circuit 1
The superimposed signal that has passed through 4 enters the cancel circuit 16. The AGC circuit 14 functions to maintain a constant value by using a part of the handwritten signal in response to level fluctuations in the superimposed signal received over a line or the like. Cancel circuit 16
A handwritten transmission signal 324 included in the superimposed signal entering the
334 and does not appear on terminal 19. The detection circuit 1 detects the handwriting vertical position signal 324.
At 7, a signal 325 corresponding to the handwritten vertical position signal inputted to the terminal 3 is generated and outputted to the terminal 20. Similarly, the detection circuit 18 generates a signal 335 corresponding to the handwritten horizontal position signal inputted to the terminal 4 based on the handwritten horizontal position signal 334 and outputs it to the terminal 21 . Thereby, the frequency modulated handwritten signal and the random spectrum signal can be transmitted simultaneously without affecting each other.

Next, the third illustrated embodiment will be described. The third embodiment uses a signal whose frequency changes as the handwriting position transmission signal, whereas the embodiment shown in FIG. 1 uses a signal whose amplitude changes as the handwriting position transmission signal. Components indicated by dashed symbols in the drawings operate in the same manner as in FIG. 1. 51 is a carrier wave oscillation circuit for vertical position transmission signals;
52 is an amplitude modulation circuit that changes the amplitude of the oscillation signal of the oscillation circuit 51 according to the input from the input terminal 3'; 53 is a carrier wave oscillation circuit for horizontal position transmission signals;
54 is an amplitude modulation circuit that changes the amplitude of the oscillation signal of the oscillation circuit 53 by input from the input terminal 4'; 55 is a detection circuit that detects the amplitude change value of the frequency signal transmitted through the bandpass filter 10';56; 57 is a detection circuit that detects the amplitude change value of the frequency signal that has passed through the band filter 11'; 57 is an amplitude modulation circuit that uses the output signal from the detection circuit 55 to change the amplitude of the oscillation signal output from the PLL oscillation circuit 12';
58 is an amplitude modulation circuit that changes the amplitude of the oscillation signal output from the PLL oscillation circuit 13' using the output signal from the detection circuit 56; 59 is a cancellation residual signal detection circuit that detects a cancellation residual signal from the received signal; 60; is an AGC circuit that operates based on the output of the detection circuit 59 so as to make the cancellation residual signal zero.

Next, the operation of the above circuit will be explained. As shown in FIG. 4, the transmission signal 31' is input from the terminal 2', passes through the superimposing circuit 8', the telephone line 1', the distribution circuit 9', the AGC circuit 60, and the cancel circuit 16', and then passes through the terminal 19'. leading to. The handwriting vertical position signal 321 inputted to the terminal 3' is subjected to amplitude modulation by the amplitude modulation circuit 52 on the carrier wave oscillated by the oscillation circuit 51, and a handwriting vertical position transmission signal 326 is output. Similarly, the handwritten horizontal position signal 331' is the handwritten horizontal position transmission signal 3.
36 is output. Handwritten transmission signal 326,3
36 is mixed in a mixing circuit 7', superimposed on a transmission signal 31' in a superimposing circuit 8', and transmitted to the telephone line 1'. This signal is divided by a distribution circuit 9' and filtered by bandpass filters 10' and 11'. band filter 1
At 0', the handwriting vertical position transmission signal 327 passes;
The amplitude change of this signal 327 is detected by the detection circuit 55. This detected signal 325' corresponds to the handwritten vertical position signal 321' inputted to the terminal 3', and is outputted to the terminal 20'. Similarly, the handwritten horizontal position signal 335' is output to the terminal 21'. On the other hand, in the PLL oscillation circuit 12', the input signal 327 advances the phase by the phase delayed by the bandpass filter 10', and generates a signal 328 whose phase is inverted. In the amplitude modulation circuit 57, the signal 328 is sent to the detection circuit 55.
The output is used as a signal 329 whose amplitude changes. Similarly, the signal from the PLL oscillation circuit 13' becomes a signal 339 whose amplitude changes at the output of the amplitude modulation circuit 58. The handwritten transmission signal included in the superimposed signal entering the cancel circuit 16' is canceled by the handwritten signals 329 and 339 having opposite phases, but the signals 31 and 32
Since the superimposed signals of 6 and 336 are generally subject to level fluctuations on the telephone line 1', the handwritten signals 329 and 3
39 alone will not be able to completely cancel, and some cancellation will remain. Therefore, by detecting either the handwritten signal 329 or 339 by the cancellation residual signal detection circuit 59 and operating the AGC circuit to make this cancellation residual zero, the handwritten signal appearing at the terminal 19' disappears. This allows the amplitude modulated handwritten signal and the random spectrum signal to be transmitted simultaneously without affecting each other.

As explained above, according to the present invention, it is possible to transmit a random spectrum signal such as a telephone signal and a relatively narrow spectrum signal such as a handwritten signal without being influenced by each other, and the transmission path can be This greatly contributes to economicization, etc.

[Brief explanation of drawings]

1 and 3 are circuit diagrams showing an embodiment of the present invention. FIG. 2 is a circuit diagram of the apparatus of the first illustrated embodiment, and FIG. 4 is a circuit diagram of the apparatus of the third illustrated embodiment, with respective transmission signal paths and handwriting transmission signal paths attached thereto. 1, 1'... General telephone line for voice, 2, 2'...
Telephone terminal, 3, 3'... Handwritten vertical position signal input terminal for sending end, 4, 4'... Handwritten horizontal position signal input terminal for sending end, 5... Vertical position signal oscillation circuit, 6...
...Horizontal position signal oscillation circuit, 7,7'...mixing circuit,
8, 8'...superposition circuit, 9,9'...distribution circuit, 1
0, 10', 11, 11'...Band filter, 1
2, 12', 13, 13'...PLL oscillation circuit, 1
4...AGC circuit, 15,15'...Mixed circuit, 1
6, 16'... cancel circuit, 17, 18...
Detection circuit, 19, 19'...Output terminal, 20, 2
0', 21, 21'... terminal, 51... vertical position signal oscillation circuit, 52, 53... amplitude modulation circuit, 54
... Horizontal position signal oscillation circuit, 55, 56 ... Detection circuit, 57, 58 ... Amplitude modulation circuit, 59 ... Cancellation residual signal detection circuit, 60 ... AGC circuit.

Claims (1)

[Scope of Claims] 1. A handwriting transmission superimposition transmitting end device that superimposes and transmits a handwritten transmission signal and a random spectrum signal by frequency modulation, and a handwriting transmission superimposing receiving end device that separates the two signals on the receiving side. The handwriting transmission superimposing sending end device includes an oscillation circuit that changes the frequency in response to the vertical position signal, an oscillation circuit that changes the frequency in response to the horizontal position signal, and a handwriting transmission between the two oscillation circuits. a mixing circuit that mixes position signals; and a superimposition circuit that superimposes an input transmission signal from a general telephone terminal and a handwriting position transmission signal from the mixing circuit; a distribution circuit for distributing a superimposed signal from a handwriting transmission superimposing sending end device, a band filter for passing only a handwriting transmission vertical position signal, a band filter for passing only a handwriting transmission horizontal position signal, and a band filter for passing only a handwriting transmission horizontal position signal; A PLL oscillation circuit controlled by a position signal and a PLL controlled by the handwritten horizontal position signal
an oscillation circuit, a mixing circuit that mixes the handwriting transmission vertical position signal and the handwriting transmission horizontal position signal from both the PLL oscillation circuits, an AGC circuit controlled by the handwriting transmission vertical position signal, and the AGC circuit. a cancel circuit that cancels only the handwritten transmission signal using the output signal of the mixing circuit without affecting the telephone transmission signal with a superimposed signal passing through the circuit; and detecting the outputs of the two PLL oscillation circuits; A handwriting transmission device comprising: a detection circuit that outputs a vertical position signal and a horizontal position signal, respectively. 2. Consists of a handwriting transmission superimposing transmitting end device that superimposes and transmits a handwritten transmission signal and a random spectrum signal by amplitude modulation, and a handwriting transmitting superimposing receiving end device that separates the two signals on the receiving side, The handwriting transmission superimposing sending end device includes an amplitude modulation circuit that changes the amplitude in response to the vertical position signal, an amplitude modulation circuit that changes the amplitude in response to the horizontal position signal, and a handwriting transmission position signal from both of the amplitude modulation circuits. a mixing circuit for mixing, and a superimposition circuit for superimposing the input signal of the general telephone terminal and the handwriting position transmission signal, wherein the handwriting transmission superimposing receiving end device receives the input signal from the handwriting transmitting superimposing sending end device. A distribution circuit that distributes the superimposed signal, a band filter that allows only the handwriting transmission vertical position signal to pass, a band filter that allows only the handwriting transmission horizontal position signal to pass, and the handwriting transmission vertical position signal. PLL oscillation circuit and PLL controlled by the handwritten horizontal position signal
an oscillation circuit, a detection circuit for detecting a change in the output level of the bandpass filter, an amplitude modulation circuit for changing the oscillation signal of the PLL oscillation circuit according to the output of the detection circuit, and an amplitude modulation circuit for detecting both modulated waves. A mixing circuit for mixing, a cancel circuit for canceling only the handwritten transmission signal by using the output signal of the mixing circuit without affecting the telephone transmission signal with a superimposed signal passing through the AGC circuit described later, and the cancel circuit. A handwritten note characterized by comprising: a cancel residual signal detection circuit that detects and outputs the remainder of the signal to be canceled using the output of the cancel residual signal detection circuit; and an AGC circuit that is controlled by the output of the cancel residual signal detection circuit. Transmission device.