JPS5843945B2 - Two-color facsimile transmitter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-color facsimile transmission device that can communicate with existing monochrome facsimile devices.

Generally, existing monochrome facsimile apparatuses employ the AM modulation method due to its superior transmission quality.

On the other hand, since two-color facsimile machines have a large amount of information, they employ, for example, an AM-PM modulation method.

Therefore, when transmitting from a two-color facsimile machine to a monochrome facsimile machine, it is fully expected that one of the two colors will be omitted.

To solve these drawbacks, a separate modulation circuit must be provided in the two-color facsimile transmitter.

The present invention provides a two-color facsimile transmission device that can communicate with existing monochrome facsimile devices without providing a separate modulation circuit.

An embodiment of the present invention will be described below with reference to the drawings.

Note that for convenience of explanation, two colors are determined in advance.

That is, - the color is black and the others are red.

FIG. 1 is a block diagram of a transmitting section of a two-color facsimile machine according to an embodiment of the present invention.

In the figure, 1 is the original to be sent, 2 is the light source, 3 is the lens, and 4
is a half mirror equipped with a filter function that reflects red light and transmits light of colors other than red.

5A and 5B are photoelectric converters, 6 is an addition circuit, and 7 is a subtraction circuit.

8A and 8B are amplifiers, 9 is an inverting circuit, 10 is an analog switch, and 11 is a resistor.

Reference numeral 12 denotes a Linda modulator, which has a characteristic of modulating the carrier wave so that its phase differs by 180 degrees when the input image signal is positive and when it is negative.

13 is a pulse generator that outputs a signal of a predetermined frequency to create a carrier wave.

14 is a network control circuit; 15 is a discrimination circuit that discriminates whether the receiving side is a monochrome facsimile machine or a two-color facsimile machine and outputs the result; and 16 is a gate circuit.

The operation of this device will be explained below.

First, the operation when the receiving side is a two-color facsimile machine will be explained with reference to FIG.

First, when exchanging control signals between eight facsimile machines, the discrimination circuit 15 extracts the control signal sent from the receiving side from the network control circuit 14 and determines whether the receiving side is a two-color facsimile machine or a monochrome facsimile machine. Determine.

This can be easily determined because the frequency of the control signal is determined in advance for each facsimile machine model.

Since the receiving side is now designated as a two-color facsimile IJ device, the output signal a of the discrimination circuit 15 is at a high level ■1.

Next, the creation of image signals will be described.

A transmission document 1 is scanned by a scanning beam from a light source 2, and the reflected light passes through a lens 3 and reaches a half mirror 4.

Of the reflected light that has reached the half mirror 4, red light is reflected by the half mirror 4, guided to the photoelectric converter 5B, and subjected to photoelectric conversion.

Here, an image signal indicating red is obtained.

Furthermore, among the reflected light that has reached the half mirror 4, light of colors other than red passes through the half mirror 4, is guided to the photoelectric converter 5A, and is subjected to photoelectric conversion.

Here, an image signal C is obtained that represents a color that is a generalization of colors other than red.

The signals S and C are input to an adder circuit 6 and a subtracter circuit 7, respectively, and the output of the adder circuit 6 is an image signal d covering the entire visual sensitivity range, and the output of the subtractor circuit 7 is an image signal d of red. e is obtained.

That is, an image signal indicating red is obtained from the photoelectric converter 5B, but the reflection characteristics of the half mirror 4 are not necessarily sufficient and components other than red are also reflected, so output is also output from the portion other than the red color.

Therefore, by subtracting the output of the photoelectric converter 5A from the output of the photoelectric converter 5B, other components are made to appear on the negative side, and then by slicing and removing the negative side, an image signal e indicating red can be obtained. It will be done.

Next, the image signal d is amplified by an amplifier 8A and then divided into two parts, one of which passes through a reflection circuit 9 and then passes through an analog switch 10.
One of the selected terminals 17 of the analog switch 10 and the other terminal 18 of the analog switch 10 appear as they are.

Further, the previous image signal e is input to the gate circuit 16 after being amplified by the amplifier 8B.

At this time, the gate circuit 16 outputs the output signal a of the discrimination circuit 15.
is open because it is at a high level.

Therefore, the image signal d passes through the gate circuit 16 and becomes the control signal f for the analog switch 10.

When this control signal f is 1+“, analog switch 1
The selection terminal 19 of 0 selects the selected terminal 17, and selects the selected terminal 18 when the control signal f is 50''.

In other words, the selection terminal 19 has an image signal of a component other than the red signal on the 1,000" side, with the reference voltage level y% 0" as the center, and a signal that is an inversion of the red signal on the 9-" side.
ternary analog image signals g are obtained.

This signal g is biased with a predetermined voltage to become a signal and is input to the ring modulator 13.

The ring modulator 13 uses this signal to modulate a signal with a predetermined frequency output from the pulse generator 13. When the signal is positive, the carrier wave has a phase of, for example, 10", and the signal has a positive phase. When the carrier wave is negative, amplitude modulation is performed so that the carrier wave has a phase shifted by 180 degrees, for example, 1π''.

In this way, the transmission signal i is obtained and the network control circuit 14
The signal is then output from the terminal 20.

If this transmission signal i is demodulated on the receiving side in the reverse order of modulation, two-color image signals can be obtained.

Next, the operation when the receiving side is an existing monochrome facsimile machine will be explained using FIGS. 1 and 3.

At the beginning of facsimile IJ communication, when the discrimination circuit 15 determines that the receiving side is a monochrome facsimile device,
The output signal a' of the discrimination circuit 15 becomes low level L, and the gate circuit 16 is closed.

On the other hand, from the image signals b' and C' obtained by decomposition by the half mirror 4, a signal d' is sent to the adder circuit 6 as described above.
is generated, and the subtraction circuit 7 generates a signal e'.

This signal e' is amplified by the amplifier 8B and input to the gate circuit 16, but since the gate is closed, the output control signal f' of the analog switch 10 remains at O" and does not change.

Therefore, the selection terminal 19 of the analog switch 10 continues to select the selected terminal 18.

That is, the signal d' is amplified by the amplifier 8A and directly becomes the signal g'.

This signal g' is level-converted to obtain a signal h', which is further input to the ring modulator 12 to become a signal i'.

This signal i' is different from the signal i (FIG. 2) transmitted when the receiving side uses a two-color facsimile, and the phase of the carrier wave is not inverted even in the case of red.

In other words, this signal 1 can be applied to existing monochrome facsimile machines.
′, a reproduced recorded image can be obtained without omitting red or black.

As described above, according to the present invention, it is possible to realize a two-color facsimile transmitter that can communicate with both a two-color facsimile receiver and an existing monochrome facsimile machine without providing a new modulation circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a two-color facsimile transmitter according to an embodiment of the present invention, and FIGS. 2 and 3 are waveform diagrams for explaining the operation of FIG. 1. 1... Original to be sent, 2... Light source, 3...
...Lens, 4...Half mirror-15A,
5B...Photoelectric converter, 6...Addition circuit, 7...Subtraction circuit, 8A, 8B...Amplifier, 9...Inversion Circuit, 10...analog switch, 12...ring modulator,
14...Network control circuit, 15...Discrimination circuit, 16...Gate circuit.

Claims (1)

[Claims] 1. means for decomposing an image signal obtained by scanning a transmission document by an optical device into a predetermined first color signal and a second color signal summarizing colors outside the first inclusion; means for creating a third signal covering the entire range of visual sensitivity using the first and second color signals; means for creating a fourth signal by inverting the third signal; means for determining whether a receiving side is a two-color facsimile machine or a monochrome facsimile machine; a switching means for switching between a third signal and a fourth signal using a control signal; and an output signal of the discriminating means and the first color signal. means for creating the control signal of the switching means using the switching means; means for converting the output signal of the switching means into a predetermined voltage level; A two-color facsimile transmission device comprising: means for modulating a carrier wave by shifting the carrier wave.