Note: Descriptions are shown in the official language in which they were submitted.
1~176~S
BACKGROUND OF THE INVENTION
. . . _ . _
The present invention relates to a system to
superpose a picture and/or a character pattexn on an original
facsimile pattern which is in the modulated analog signal
form of amplitude modulation (AM), amplitude-phase modulation
(AM-PM), frequency modulation (FM) and/or phase modulation (PM).
In a facsimile transmission system and/or a
facsimile exchange system, superposition of an additional
pattern on the original facsimile pattern is sometimes
required. That additional pattern is, for instance, the date
and/or the time that the facsimile signal is transmitted,
calling subscriber recognition information, charge information,
or other comments for communication purposes.
According to a prior apparatus of this kind,
a modulated facsimile signal is temporarily received by
a facsimile receiver, and the baseband signal in the analog
form thus obtained is converted to a digital form through
digital sampling p~ocess. Then the facsimile signal in
the digital form thus obtained is added logically to a
character signal in the digita] form obtained from the
control apparatus for character generation, and then the
resultant logical sum is transmitted through a facsimile
transmitter.
However, said prior facsimile superposition system
has the disadvantages that a facsimile transmitter is r~ecessary,
thus the system structure is complicated, and further a
picture quality is deteriorated since a facsimile signal is
converted to a baseband signal for digital sampling.
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SUMMA Y OF THE INVENTION
It is an ob~ect, therefore, of the present inven-
tion to overcome the disadvantages and limitations of a
prior facsimile superposing system hy providing a new and
improved facsimile superposing system.
It is also an object of the present invention to
provide a facsimile superposing system to which an addi-
tional pattern is superposed on an original pattern without
demodulating the original facsimile signal. That is to say,
the analog type facsimile signal modulated by amplitude
modulation, amplitude-phase modulation, frequency modula-
tion, and/or phase modulation is directly superposed with
an additional pattern.
The above and other objects are attained by a facsimile
superposing system for superposing an additional pattern on
an original pattern comprising an input means for receiving
the analog t~pe original facsimile pattern signal modulated
by either the AM, AM-PM, FM or PM systems, a digital memory
having the capacity enough to store the additional pattern
to be superposed, an insertion circuit having a first
input terminal connected to said input means, a second input
t~rminal connected to the output of said digital memory and
an output terminal for providing the sum of the first and
the second input terminal signals, a write circuit connected
to said digital memory for writing a desired pattern into
the memory, an address circuit including a cell counter and
a line counter both connected to said memory for addressing
said digital memory, said cell counter having the capacity
equal to the number of cells in a single scanning line of
the original pattern and the line counter having the capa-
city enough to count the number of scanning lines of the
additional pattern, a cell clock generator to increment
said cell counter and the frequency of which is equal to
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the scanning frequency of the original pattern, said line
counter being incremented by the overflow pulse of said
cell counter, and output means connected to the output ter-
minal of said insertion circuit.
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BRIEF DESCRIPTION OF THE DRAWINGS
The forego m g and other ob jects, features, and
attendant advantages of the present invention will be
understood by means of the following description and accompany-
ing drawings wherein;
Fig. 1 shows the general block-diagram of the
facsimile exchange system according to the present invention,
Fig. 2 shows the tran~mission control procedure of
a typical facsimile transmission system,
Fig. 3 shows the block-diagram of the embodiment
of the facsimile superposing apparatus according to the
present invention,
Fig. 4 shows the operational timing sequence of
the apparatus in Fig. 3,
Figs. 5(A), 5(B) and 5(C) are some embodiments of
the insertion circuit 30 in Fig. 3,
Figs. 6, 7 and 8 are waveforms of the insertion
circuits in Figs. 5(A), 5(B) and 5(C), respectively,
Fig. 9(A) and Fig. 9(B) are modifications of
the insertion circuit, and
Fig. 10 is the simplified modification of the
apparatus in Fig. 3.
~716~5
DESCRIPTION OF THE PREFER~ED E~BODIMENTS
Fig. 1 shows the general block-diagram of a
facsimile exchan~e system utilizing the present invention,
in which the reference numeral 1 is the facsimile transmitter,
2 is the modulator for modulating the facsimile base band
signal from the facsimile transmitter 1 by ~M (amplitude
modulation), AM-PM (amplitude-phase modulation), FM (frequency
modulation), or PM (phase modulation). 3 is the facsimile
exchange apparatus and/or the facsimile repeater, 4 is the
demodulator for recovering the facsimile base band signal
from the modulated signal, and ~ is the facsimile receiver.
Also, 10 is the facsimile superposing apparatus inserted in
the transmission line between the output of the modulator 2
and input of the demodulator 4. Supposing that the original
pattern at the facsimile transmitter 1 is the pattern (A~ and
the additional pattern to be superposed at the facsimile
superposing apparatus is the pattern (B), then the superposed
pattern at the facsimile receiver 5 is the pattern ~C), which
is the summation of the pattern (A) and the pattern (B).
The present invention relates to superposing a pattern as
described. It should be understood in Fig. 1, that the
facsimile signal is not processed through a complicated
digital information processing technique, but is transmitted
in a simple analog form and is superposed with an additional
pattern.
Fig. 2 shows the transmission control procedure
of a typical facsimile transmission system according to
recommendation T30 of CCITT (International Telegraph and
Telephone Consultive Committee which i5 a subsidiary organization
of the United Nations). In Fig. 2, the facsimile
il~7~;~S
transmitter (FAX-S) forwards the phasing signal (P~IS) which
is the repetition of the O-phase signal and the ~-phase
signal for synchronization between the transmission side
and the reception side. Said O-phase signal and the ~-phase
signal are 2,100 +10 Hz in said recommendation with a
duration of less than 6 seconds, and the beginning point of
either O-phase signal or ~-phase signal is the reference
point of the synchronization. When the reception side assures
that reference point and synchronization is established
between two stations, the reception side returns the
"confirmation t~ receive" signal (CFR) which is 1080 Hz and
continues for 3 seconds +3%. When the transmission side
receives the CFR signal, the transmission side recognizes
that the reception side is ready to receive a picture and
synchronization has been established, so the transmission
side starts to forward a picture signal (PIX). When the
transmission side finishes forwarding the picture signal,
the EOM (end of message) signal is forwarded from the trans-
mission side to the reception side, and the MCF (message
confirmation) signal is returned from the reception side to
the transmission side. Thus, when the transmission side
receives the MCF signal, the sequence of facsimile trans-
mission procedures finishes.
Accordingly, the facsimile superposing apparatus
10 according to the present invention must operate in
coincidence with said facsimile transmission procedure.
Fig. 3 shows the block-diagram of the embodiment
of the facsimile superposing apparatus according to the
present invention. In the figure~ the reference numerals 12
and 12a are hybrid circuits for converting the two-wire
11~7645
system to a four-wire system or a four-wire system to a
two-wire system. The two-wire end of the first hybrid
circuit 12 is connected to the facsimile transmitter through
the transmission circuit and the modulator, and the two-wire
end of the other hybrid circuit 12a is connected to the
facsimile receiver through the transmission circuit and
the demodulator. 14 is the detector/demodulator, 16 is the
digital cell counter which has a bit capacity equal to the
number of picture cells in each scanning line of a facsimile
picture. 18 is a line counter which has a bit capacity equal
to the cells in the vertical direction of a facsimile picture,
and is incremented by an overflow pulse of said cell counter 16.
20 is the digital memory for storing the pattern to be
superposed (see the symbol (B) in Fig. 1), and said memory
is a read-only-memory (ROM) or a random access memory (RAM).
The address for reading out said memory is determined by
the outputs of said cell counter 16 and the line counter 18.
22 is the memory-write circuit for changing the content of
the memory. The change of content of the memory is performed
when the pattern to be superposed must be changed, for instance,
when the pattern to be superposed is a date, that date must
be changed every day. 24 is the CFR detector, 26 is the AND
circuit, 28 is the cell clock generator which generates a
frequency signal equal to the scanning frequency of the
picture signal, and 30 is the signal insertion circuit which
superposes the additional pattern from the second input
terminal of the line (q) on the original pattern of the
first input terminal of the line (p), thus the superposed
pattern is provided at the output terminal on the line (r).
3~ The structure of the insertion circuit depends upon the
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modulation system of the facsimile system (AM, AM-PM, FM,
or PM), and will be described later.
~t the initial status, it is supposed that the
output of the CFR detector 24 is "low", then the AND circuit
26 is open, and the line counter 18 is cleared through the
CR terminal. Then the output (q) of the memory 20 is "low"
level. It is assumed that the input terminal (p) is
directly connected to the output terminal (r) of the insertion
circuit when the output (q) of the memory 20 is "low", and
when said output (q) of the memor~ 20 is "high", the output
(q) of said memory 20 is applied to the output (r) of the
insertion circuit 30. The cell counter 16 is cleared through
the terminal CR every time the synchronization signal from
a facsmile transmitter is provid~d at the output of the
detector/demodulator 14 until the CFR signal is detected.
Then the content of the cell counter 16 is incremented by
the output of the cell clock yenerator 28 and said content
reaches full (for instance, 1728) when next synchronization
signal appears on the output of the detector/demodulator 14.
Fig. 4 (in particular the left half of Fig. 4)
shows the sequence of the above operation, in which (a) is
the output of the detector/demodulator 14 which provides the
synchronization signal (S), (b~ is the output of the CFR
detector 24, (c) is the output of the cell counter 16, (d) is
the output of the line counter 18, and (e) is the output of
the memory 20.
Accordingly, it should be understood that when
no CFR signal is detected, the first hybrid circuit 12 is
directly connected to the second hybrid circuit 12a through
the insertion circuit 30, thus the superposition apparatus
1~7t;4S
in Fig. 3 does not affect to the transmission line. Therefore,
the PHS signal (Fig. 2) can go through the apparatus freely.
Next, when a facsimile receiver returns the C~R
signal, said signal is detected by the CFR detector 24 at
the time (T3 in Fig. 4, then the output of the CF~ detector
changes to "high" level (see Fig. 4(b)). Thus, the line
counter 18 and the cell counter 16 are not cleared, instead,
the content of the cell count-er 16 and the line counter 18
indicate the address of the cell which corr3sponds to the
instantaneous scanning signal of the facsimile signal.
According to the address thus indicated, the memory 20
provides the output signal which is applied to the insertion
circuit 30 and the pattern from the memory 20 is superposed
on the original pattern.
Now, the structure and the operation of the insertion
circuit 30 will be described.
In Fiys. 5(~), 5(s) and 5(C), OP shows an operational
amplifier, Rl, R2, R3, R4 and R5 are resistors, FET, FETl and
FET2 are field effect transistors, and the terminals p, q
and r correspond to the same symbols of the insertion circuit
in Fig. 3.
Fig. 5(A) is the first embodiment of the insertion
circuit which is utilized for AM (amplitude modulation),
or Ar~-PM (amplitude-phase modulation) modulated facsimile
signals. In Fig. 5~A), when the level at the terminal (q)
is "low", the FET is cut off and the input terminal (p) is
directly connected to the output terminal (r) through the
operational amplifier, thus, the AM waveform of the facsimile
signal (see Fig. 6(a)) is directly output to the terminal (r).
On the other hand, when the terminal (q) is in the "high"
state (see Eig. 6(b)), then the FET conducts and the terminal
(p) is grounded through said field effect transistor FET.
Therefore, the input signal at the terminal (p) does not
appear at the output terminal. Thus, the amplitude of the
input signal is suppressed. The suppression of the input
signal causes the picture signal to change from white to
black. In the waveforms in Fig. 6, the waveform (a) is
the AM modulated facsimile signal, (a') is the base band
signal of the waveform ta), (b) is the additional signal to
be inserted on the terminal (q), (c) is the superposed
output siynal on the terminal (r) and (c') is the base band
signal of the waveform (c). ln those drawings, it should be
understood that the picture signals b4 and b6 are suppressed.
Fig. 5(B) is the second embodiment o the insertion
circuit in Fig. 3, and is utiliæed for AM, AM-PM or FM
modulated facsimile signals. In Fig. 5(s), according to
the level on the insertion terminal (q), the field effect
transistors FETl and FET2 are cut off or conductive. When
the first field effect transistor FETl is conductive, the
output of the oscillator is grounded, and when the second
field effect transistor FET2 is conductive Lhe terminal (p) is
grounded. Of course the grounded signal does not appear on
the output terminal (r). Therefore, according to the level
at the terminal (q), either the input terminal (p) or tl~e
output of the oscillator OSC is connected to the output
terminal (r) through the operational amplifier OP.
The frequency of the os il~ator OSC is the same as that of
the picture signal in the AM or AM PM systems, or said
frequency is the same as the blac~ frequency or the white
frequency in the FM system.
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645
Fig. 7 shows the operational waveforms of the
circuit in Fig. 5(B), and (a) shows the input waveform at
the in~ut terminal (p), (a') is the base band signal of
the waveform ~a), (b) is the additional signal at the terminal
(q), (c) is the superposed output signal at the output
terminal (r), and (c') is the base band signal of the wave-
form (c). It should be understood in Fig. 7, that the signals
are superposed at the cells b3 and b6.
Fig. 5(C) is the third embodiment of the insertion
circuit according to the present invention, and this embodiment
is utilized for AM-PM, or PM modulated facsimile signals.
In Fig. 5(C), the input signal applied to the negative terminal
(-) of the operational amplifier OP, is inverted while the
signal applied to the positive terminal (+) of the operational
amplifier OP is not inverted in the operational amplifier.
Therefore, by designing the value of the resistance of Rl, R2
and R3 appropriately, the inverted signal is obtained when
the FET is conductive, while the non-inverted signal is
obtained when the FET is cutoff. Thus, the signal at the
insertion terminal (q) can control the phase at the output
terminal (r).
Fig. 8 shows the operational waveforms of the
circuit in Fig. 5(C), when that circuit is applied to AM-PM
modulated facsimile signals. In Fig. 8, (a) shows the input
AM-PM facsimile signal, (a') is the base band signal of
the waveform (a), (c) is the superposed output signal at
the output terminal (r), and (c') is the base band signal
of the waveform (c~ It should be understood that the output
signal on the waveform (c) is inverted at the timing b3, b4
and bg. Therefore, the demodulated signal (waveform (c')) has
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a thin spot of black signal B at the timing b3, b4 and bg.
Thus, an additional pattern is inserted as a black spot in
an original picture.
Next, some modifications of the present facsimile
superposing system will be described.
Fig. 9(A) and Fig. 9(s) are two alternatives of
the insertion circuit in Fig. 5(A). In Fig. 9(A), the photo-
coupler PC is controlled to be either conductive or cut off
by the insertion signal at the terminal (q) through the driver
transistor Tr. Then, when the photo-coupler is cut off
the input facsimile signal is suppressed. In Fig. 9(B),
the complementary metal-oxide-semiconductor C-MOS is
controlled to be conductive or cutoff by the insertion signal
at the terminal ~q), and of course when that C-MOS is cutoff,
the facsimile signal is suppressed.
It should be understood that many other modification
of the insertion cir~uit, are possible to those skilled in
the art as long as that insertion circuit can be switched
by the insertion signal.
Fig. 10 is a modification of the facsimile super-
posing apparatus, and the same reference numerals as those
in Fig. 3 show the same members. In Fig. 10, means for
clearing or initializing the cell counter 16 and the line
counter 18 are omitted. Thereforet the additional pattern
is superposed in an out-of synchronization condition,
although the line repetition rate i5 the same, and the
superposed pattern will be divided into an upper poxtion
and lower portion, or a left portion and right portionO
However, if the pattern to be superposed has many repetitions
of the same string of characters, the superposed pattern is
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readable somewhere on the received copy. So, Fig. 10 provides
a simplification of the facsimile superposing apparatus.
Further, it should be understood that the present
facsimile superposing apparatus can be inserted not only in
the repeater or the exchange system, but also in the facsimile
transmitter or receiver, or an attachment of the facsimile
transmitter or receiver.
As mentioned above, according to the present
invention, the superposing of the desired pattern is performed
with a simple apparatus without demodulating the facsimile
signal to the base band signal. Therefore, the superposing
is performed without deteriorating the picture quality.
From the foregoing it will now be apparent that
a new and improved facsimile superposing system has been found.
It should be understood of course that the embodiments dis-
closed are merely illustrative and are not intended to limit
the scope of the invention. Reference should be made to
the appended claims, therefore, rather than the specification
as indicating the scope of the invention.
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