JPS6053501B2 - Image signal addition circuit for facsimile modulation signal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image signal addition circuit for facsimile modulation signals;
In particular, the present invention relates to a facsimile modulation signal image signal addition circuit that adds an additional facsimile image signal to a facsimile signal on a frequency-modulated facsimile modulation signal.

A facsimile signal obtained by scanning an original image to be transmitted is modulated and transmitted as a facsimile modulated signal. It is desirable to optionally add an additional facsimile image signal, such as a date, to the facsimile modulated signal. Conventionally, this type of device receives a facsimile modulation signal once in a receiving device, samples the resulting base hand signal in binary form, converts it into a digital signal, and outputs it from a control device for adding the facsimile image signal. The facsimile modulation signal is logically summed with a digital control signal, and the resulting signal is again converted into a facsimile modulation signal, which is then transmitted from the transmitter.

For this reason, a transmitter/receiver is required, which makes the circuit configuration complicated, and the facsimile modulation signal is converted into a baseband signal and binary sampling is performed, which causes image quality deterioration. . In order to solve this problem, the present invention adds a facsimile image signal to the facsimile modulation signal by changing the carrier frequency of the frequency-modulated facsimile modulation signal. explain.

FIG. 1 shows an embodiment of the present invention, in which 1 is a facsimile transmission device, 2 is a relay device in facsimile communication, 3 is a synchronization signal detection device, 4 is a control device for adding facsimile image signals, and 5 is a carrier wave frequency. generation circuit, 6 is a signal addition device, 7
is a facsimile receiving device.

Also, Fig. 2 shows the signal waveform in this embodiment, and 8
is a facsimile baseband signal waveform, 9 is a synchronization signal indicating the start of scanning, 10 is a time axis, 11 is a facsimile modulation signal waveform obtained by frequency modulating the baseband signal waveform 8, and 12 is a facsimile modulation signal waveform. The carrier frequency at points B3, b, b5 of the modulated signal waveform 11 is changed to a frequency corresponding to a black signal, and 13 represents the baseband signal waveform obtained by demodulating the waveform 12.
The set transmission original image of the facsimile transmitter 1 is scanned and converted into an electrical signal by photoelectric conversion.

A synchronization signal 9 indicating the start of each scan is added to the electrical signal and converted into a baseband signal 8. Thereafter, the signal is frequency modulated and sent out from the facsimile transmitter 1 as a facsimile modulated signal 11. In the relay device 2 in facsimile communication, . The synchronization signal detection device 3 extracts a synchronization signal from the facsimile modulation signal 11 to be relayed, and the signal addition device 6 uses this synchronization signal and the control signal from the facsimile image signal addition control device 4 that has already been created. Using the carrier wave frequency generation circuit 5 of The carrier wave frequency of the axis modulation signal 11 is switched to the carrier wave frequency equivalent to the black signal.

The facsimile modulation signal 12 is the facsimile modulation signal 11
B3, b4, l). It is transmitted from the relay device 2 to the facsimile receiving device 7. The facsimile modulated signal 12 received by the facsimile receiving device 7 is demodulated and then decoded into a baseband signal 13 to reproduce the transmitted original image. Since the carrier frequency of the demodulated baseband signal 13 at the B3, b, kg points has been changed by the relay device 2, the B3, b4, kg points have a black level. In other words, an additional signal is added to the transmitted original image (signal 8) as signal 1.
It becomes possible to add black level points in the form of black level points B, , b4, and b5 in 3. In this way, the facsimile modulation signal that is sequentially relayed in the relay device is monitored and the carrier frequency is changed based on the synchronization signal for each scan, so that the facsimile image signal is added to the facsimile modulation signal. There is no need to convert it to a signal, the circuit configuration for adding the facsimile image signal becomes simple, and the facsimile image signal can be added without deteriorating the image quality due to conversion to a baseband signal. . As explained above, the facsimile image signal can be added to the facsimile modulation signal by changing the carrier frequency of the frequency-modulated 7-axis modulation signal in the repeater, so there is no need to convert the facsimile modulation signal to a baseband signal. This has the advantage that a facsimile image signal can be added with a simple circuit configuration and without deterioration of image quality due to conversion to a baseband signal.

In the above embodiments, the additional circuit has been described as existing in a relay device, but the present invention is not limited thereto, and it goes without saying that it can be applied as a facsimile terminal device or an additional device to a facsimile terminal device. .

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the apparatus of the present invention, and FIG. 2 shows an example of signal waveforms in this embodiment. In the figure, 1 is a facsimile transmission device, 2 is a relay device, 3 is a synchronization signal detection device, 4 is a facsimile image signal addition control device, 5 is a carrier frequency generation circuit, 6 is a signal addition device,
7 represents a facsimile receiving device.

Claims (1)

[Claims] 1. In facsimile communication using a facsimile modulation signal obtained by frequency modulating a facsimile signal, a detection device for monitoring the facsimile modulation signal is provided, and
An image signal addition control device is provided that changes the carrier frequency of the facsimile modulation signal in accordance with the additional facsimile image signal to be added to the facsimile signal, and according to instructions from the control device, the additional facsimile image signal to be added The carrier frequency of the facsimile modulation signal is changed in accordance with the position of the facsimile modulation signal, and the additional facsimile image signal is added to the facsimile signal demodulated on the receiving side in a form corresponding to the frequency change. An image signal addition circuit for facsimile modulation signals, characterized in that it is configured as follows.