JPS6030470B2 - Signal density conversion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal density conversion method for converting the density of a serial signal such as a facsimile signal.

In facsimile communication, it is possible to send documents even if the size of the documents to be sent differs, but various methods have been proposed to simplify the device by always receiving and reproducing documents at a fixed size on the receiving side. .

In that case, the adjustment can be roughly divided into optical system adjustment and electrical system adjustment. Adjustment of the optical system involves adjusting the angle of view of the lens system, but a configuration that adjusts the angle of view without causing image distortion has the disadvantage of being complicated and expensive. Also, the adjustment of the electrical system is
This can be done by switching the sampling period of the output signal of the light-receiving element, but simply increasing the sampling period has the disadvantage that the resolution decreases. The present invention
This method has improved the above-mentioned drawbacks, and its purpose is to convert the signal density according to the size of the transmitted original without reducing the resolution.

Examples will be described in detail below. FIG. 1 is an explanatory diagram of the main parts of a facsimile transmitter, in which 1 is a photoelectric conversion element such as a photodiode array or a charge transfer device (CCP), 2
3 is a transmission document, 4 is a signal converter, and 5 is a buffer memory.

The lens 2 has an angle of view relative to the largest size of the original to be transmitted 3, and the angle of view of the lens 2 is not adjusted when the size of the original to be transmitted 3 is different as shown by the dotted line. The photoelectric conversion element 1 operates according to the clock CLI, and the signal conversion section 4 samples the output of the photoelectric conversion element 1 according to the clock CL2, sends it to the buffer memory 5 using the clock CL3 as a transmission clock, and uses a run (not shown) as necessary. In addition to the length compression means, the data is sent to the receiving side. FIG. 2 is a block diagram of a main part of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of its operation. The output signal a of the photoelectric conversion element 1 operated by the clock CLI is applied to the gates GI to G3.

Gate GI is an AND gate, gate G2 is an invite gate, and gate G3 is an exclusive OR gate.
Also, the fritz flop FFI is ku. The clock CL2 and the flip-flop FF2 operate with the clock CL3, and the Q terminal output signal b of the flip-flop FFI is output from the flip-flop F.
The Q terminal output signal is applied to the J terminal and the K terminal of F2, respectively, and the Q terminal output signal c of the flip-flop FF2 is outputted as a converted output signal from the output terminal OUT. CL2, CL3, a, b, and c in FIG. 3 indicate an example of signals having the same sign in each part in FIG.
Gate G only when different from output signal c of Q terminal of F2
When the output signal of 3 becomes "1", gates GI and G2 are opened. If the signal a is "1", the flip-flop FFI is set at the timing of the clock CL2, and if the signal a is "0", it is reset.

That is, signal a is sampled by clock CL2,
Flip-flop FFI performs an inverting operation when input signal a is opposite to output signal c of flip-flop FF2.
Note that it is necessary to select the clock CL2 to have the same repetition cycle as the clock CLI or a cycle longer than that of the clock CLI. Flip-flop FF2 operates in accordance with clock CL3 applied to its clock terminal CL, and performs an operation equivalent to sampling the output signal b of flip-flop FFI using clock CL3.

Therefore, signal density conversion can be performed by setting the clock CL3 to a speed corresponding to the signal sending speed.
As can be seen from the relationship between a and c in FIG.
It is thinned out in accordance with the speed relationship of L1 and CL3, and isolated "1" or "0" is not thinned out and is sent to the output terminal OU.
It will be outputted from T as an output signal c. That is,
For thin lines or thin blank areas in the transmitted document, the input signal a becomes an isolated "1" or "0", and this information is preserved even when signal density conversion is performed, so on the receiving side, thin lines or thin blank areas are Isolated "1" or "0" indicating a blank area can be reproduced and recorded, and therefore, a decrease in resolution can be suppressed. As a specific example, if the photoelectric conversion element 1 has a 1024-pit configuration and a transmission document reading operation is performed with a clock CLI of 102.4KH2, B
For the 5th version of the transmitted original, the output signal a of the photoelectric conversion element 1
102. ” The data is sampled using the KHZ clocks CL2 and CL3, and 768 bits are added to the buffer memory 5 by means such as a counter.

That is, since the B5 original to be sent is read using 768 bits of the 1024-bit photoelectric conversion element 1,
Only the correction signal for the B5 version of the transmitted manuscript will be transmitted. Also, for A4 size originals, 1024-bit photoelectric conversion element 1 is used.
The output signal a of the photoelectric conversion element 1 is 1024K.
HZ clock CL2 is sampled, then 7 balls H
It is sampled by Z clock CL3. Therefore 10
The 24-bit signal will be converted to a 7-bit coarse density signal. That is, the signal density is converted, for example, from a to c in FIG. On the receiving side, the number of bits corresponding to one scanning line is 768 for reception and reproduction.
Even for sent manuscripts with different sizes between 5th edition and A4 edition,
It is possible to receive and reproduce the same size with almost no reduction in resolution. As explained above, the present invention provides an exclusive OR gate G that compares the input signal a according to the first clock CLI and the density conversion output signal c.
A second clock CL2 having the same or shorter cycle as the first clock CLI is connected to the clock terminal CL, and the output signal of the comparing means is connected to the input terminal J,
a first flip-flop FFI which is applied to each of
and a second flip-flop FF2 to which the output signal of the first flip-flop FFI is applied to input terminals J and K, and a third clock CL3 having a period corresponding to the signal transmission density is applied to the clock terminal CL. Well, this second
The output signal c of the flip-flop FF2 is used as the density conversion output signal, and the first and third clocks C
It becomes possible to perform signal density conversion corresponding to L1 and CL3.

Furthermore, since isolated pulse-like input signals are preserved through signal density conversion, there is an advantage that signal density conversion can be performed without reducing resolution. Therefore, when applied to a facsimile transmitter, the signal density is converted and transmitted so that documents of different sizes can be received and reproduced at the same size on the receiver side without adjusting the lens system. becomes possible.

In addition, isolated ``1'' or '' other than facsimile signals
It can also be applied to serial signals that preserve '0' and require signal density conversion.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the main parts of a facsimile transmitter, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is an operational diagram thereof. 1 is a photoelectric conversion element, 2 is a lens, 3 is a transmission document, 4 is a signal converter, 5 is a buffer memory, FF1 and FF2 are flip-flops, GI to G3 are gates, and CLI to CL3 are clocks. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 Comparing means for comparing an input signal according to a first clock with a density conversion output signal, a second clock having the same or shorter cycle as the first clock, and an output signal of the comparing means are added to each input terminal,
A first flip-flop is inverted in response to the inconsistent output signal of the comparing means, and the output signal of the first flip-flop is applied to the input terminal, and a third clock having a period corresponding to the signal transmission density is applied to the clock terminal. and a second flip-flop added to the signal density conversion method, the signal density conversion method comprising: a second flip-flop added to the signal density conversion method, and an output signal of the second flip-flop is sent out as the density conversion output signal.