Television receiver

A television receiver converts a television signal of a standard television system currently employed into a signal at a horizontal scanning frequency of n (an integer of 2 or more) times that of the original television signal, so that it can visually reproduce any one of a television signal of the standard television system and a television signal of a second television system, which has a horizontal scanning frequency of about n times that of the television signal of the standard television system. When receiving the television signal of the standard television system, the horizontal deflection circuit operates at a horizontal scanning frequency n times that of the standard television system. When receiving the television signal of the second television system, it operates at the horizontal scanning frequency of the second television system. For the reproduction of the converted signal with the n times horizontal scanning frequency, the interval between the adjacent scanning lines may properly be adjusted by moving them at the horizontal scanning period of the standard television system in the vertical scanning direction.

BACKGROUND OF THE INVENTION 
The present invention relates to a compatible television receiver which can 
visually reproduce a television signal of a standard television system and 
a television signal of a second television system having a horizontal 
scanning frequency n times that of the television signal of the standard 
television system. 
The standard television systems now employed are typically an NTSC system, 
a system, and a SECAM system. In the NTSC system, for example, the 
number of the horizontal scanning lines is 525 and the number of frames 
per second is 30. In an enlarged picture size of the recent television set 
of any system, the scanning line intervals are widened and distinctive on 
the screen, thus providing a coarse picture. Particularly in present times 
a large sized picture is often required and the development of a high 
resolution picture television signal is urgently required for improving 
the poor resolution in the television picture. For this reason, a high 
definition television system (HDTV) having a number of the scanning lines 
two to three times that of the currently used standard television system 
and with a frequency band-width 5 to 10 times that of the standard 
television system, will be employed in the near future. The HDTV already 
proposed by NHK (Nippon hoso kyokay, the Japanese national broadcasting 
corporation) has 1125 scanning lines and a 20 MHz luminance band-width. 
The HDTV processed by the EIA(Electronic Industries Association) has 1023 
scanning lines and a 21.1 MHz luminance band-width. The HDTV proposed by 
the BBC has 1501 scanning lines and a 50 MHz luminance band-width. 
Those HDTVs are now being discussed by a working group in SMPTE (Society of 
Motion Picture and Technical Engineers), which has been specially set up 
for the realization and execution of HDTV. It is believed that the 
realization of a HDTV television set, which can also be adaptable for the 
standard television system, that is, a compatible television set, will 
promote the prevalence of the HDTV, particularly in a transition present 
transient period to the HDTV days. 
In recent times, there has been an increasing demand for character display 
systems for displaying alphanumeric characters, symbols and the like, 
which are used in the terminal equipment of the computer, and a graphic 
display for displaying graphs, patterns and the like. In some display 
devices of this type, in order to improve the amount of information 
handled, the luminance signal band-width is widened and the number of 
scanning lines is increased to about two times that of the standard 
television system. If those display devices are so designed as to visually 
reproduce a television signal of the standard television system, the 
display device can display the signals from VTR or cameras, thus finding a 
wide use. In this respect, it is desired to realize such compatible 
display devices as soon as possible. 
In realizing compatible television receivers, a problem is encountered in 
that it is difficult to use a deflection circuit common for two the 
television systems for their signal processing, since the horizontal 
scanning frequencies of the two television systems are greatly different 
from each other. 
Two methods to cope with this problem have been known. One of those methods 
is the horizontal deflection circuit is partially switched by means of a 
relay or the like so that it operates at the scanning frequency of either 
the standard television system or the second television system. The 
method, however, has a drawback of insufficiency in reliability, since 
relay means must switch-over circuit constants of a high potential circuit 
portion such as a resonance capacitor, an S distortion correcting 
capacitor, and a linearity control coil. 
The second method is that, as in the standard television system converting 
method between the NTSC, and SECAM system, a video signal of one 
television system is converted into a signal with a horizontal scanning 
frequency of the other television system, and the operating frequency of 
the deflection circuit is fixed to the scanning frequency of the other 
television system. 
However, the second method requires a frame memory and yet a large memory 
capacity. Furthermore, this method is applicable only for the conversion 
between two television systems of which the scanning frequencies are in a 
fixed relation. In this respect, this method has a poor flexibility in 
converting the television signals of the television systems one to 
another. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a simple and 
reliable television receiver which can visually reproduce a television 
signal of a standard television system and a television signal of a second 
television system with a horizontal scanning frequency about n times that 
of the signal of the standard television system. 
Another object of the present invention is to provide a means for adjusting 
an arrangement or distribution of scanning lines and signals when the 
television signal of the standard television system is converted to be 
displayed by a converted signal with a horizontal scanning frequency n 
times that of the television signal of the standard television system.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
A block diagram of an embodiment of a television receiver according to the 
present invention is shown in FIG. 1. In FIG. 1, reference numeral 10 
designates an input terminal, numeral 20 a demodulator, 30 a signal 
converting circuit, 40 a video output circuit, 50 a sync separation 
circuit, 60 a vertical deflection circuit, 70 a PLL circuit, 80 a 
horizontal deflection circuit, 90 a drive circuit, 100 an auxiliary 
deflection means, 110 an input terminal, 120 a demodulator, 130 a 
changeover switch, 140 a sync separation circuit, 150 a changeover switch, 
and 160 a changeover switch. The input terminal 10 is supplied with a 
television signal of a standard television system (a video signal of the 
NTSC system in this embodiment). The demodulator 20, widely used in a 
usual television receiver, demodulates the video signal into signals 
corresponding to primary colors, for example, R, G and B signals or Y, I 
and Q signals. In this embodiment, a case that the television signal is 
demodulated into R, G and B signals is illustrated. These signals are 
applied to the signal converting circuit 30, and after converted into a 
signal with a doubled horizontal scanning frequency, the signals are 
amplified by the video output circuit 40. Then, those signals are applied 
to a CRT (cathode ray tube) (not shown). 
The operation of an embodiment of the signal converting circuit 30 will be 
described referring to FIG. 2. FIG. 2(a) indicates an example of a signal 
obtained by the demodulator 20, and the signal is applied to the signal 
converting circuit 30. The signal converting circuit 30 has at least two 
memories. As shown in FIGS. 2(b) and (c), the circuit is so arranged that 
when one memory is in a write mode, the other is in a read out mode. The 
operation modes are inverted every horizontal scanning period of a 
television signal of the standard television system. The written signal is 
read out twice at a speed two times as fast as that at which it is written 
during the next one horizontal scanning period. Therefore, a signal shown 
in FIG. 2(d) is read out from the memory of which the operation mode is 
shown in FIG. 2(b), and a signal shown in FIG. 2(e) is read out from the 
memory of which the operation mode is shown in FIG. 2(c). A composite 
signal (f) of the signals (d) and (e) summed with each other is taken out 
as an output signal of the signal converting circuit 30. 
The sync separation circuit 50, widely used in a usual television receiver, 
separates a horizontal synchronizing signal and a vertical synchronizing 
signal from a sync signal obtained by the demodulator 20. The vertical 
synchronizing signal is supplied to the vertical deflection circuit 60 by 
way of the switch 150. The vertical deflection circuit 60 drives a 
vertical deflection coil (not shown). Meanwhile, the horizontal 
synchronizing signal is supplied to the PLL circuit 70. The PLL circuit 70 
forms a frequency twice that of the horizontal synchronizing signal on the 
basis of the horizontal synchronizing signal supplied from the sync 
separation circuit 50. The signal formed is supplied to the horizontal 
deflection circuit 80 via the switch 160. The PLL circuit 70 also produces 
a square wave with a duty ratio 50% and the same frequency as that of the 
horizontal synchronizing signal on the basis of the horizontal 
synchronizing signal supplied from the sync separation circuit 50, and 
supplies it to the drive circuit 90. 
An embodiment of the PLL circuit 70 and a waveform diagram for the 
explanation of the circuit 70 are shown in FIGS. 3 and 4. In FIG. 3, 
reference numeral 71 designates an input terminal, 72 a voltage controlled 
oscillator (VCO), 73 a frequency dividing circuit, 74 a flip-flop, and 75 
a monostable multivibrator. In FIG. 4, there are illustrated a waveform 
(a) of a horizontal synchronizing signal supplied from the sync separation 
circuit 50 in FIG. 1 to the input terminal 71, a waveform (b) of an output 
signal of the VCO 72, a waveform (c) of an output signal of the frequency 
dividing circuit 73, a waveform (d) of an output signal of the monostable 
multivibrator 74 and a waveform (e) of an output signal of the flip-flop. 
The VCO 72 generates a signal at a frequency m (m is an integer of 2 or 
more) times that of the horizontal sync signal applied to the input 
terminal 71 (in this embodiment, m=4). The output signal from the VCO 72 
is fed to the frequency dividing circuit 73. The frequency dividing 
circuit 73 frequency-divides the output signal of the VCO 72 into a signal 
with a 2/m frequency, as shown in FIG. 4(c), and feeds it to the flip-flop 
74 and the monostable multivibrator 75. The monostable multivibrator 75 
properly sets a pulse width on the basis of the signal in FIG. 4(c) 
supplied from the frequency dividing circuit 73, to reproduce a horizontal 
sync signal as shown in FIG. 4(d). The frequency of the horizontal sync 
signal obtained in the monostable multivibrator 75 is twice as high as 
that of the horizontal sync signal, shown in FIG. 4(a), applied to the 
input terminal 71. And the signal is fed to the horizontal deflection 
circuit 80 through the switch 160. Meanwhile, the output of the frequency 
dividing circuit 73 is also supplied to the flip-flop 74. The flip-flop 74 
frequency divides the output signal of the frequency dividing circuit 73 
to a signal with a halved frequency, and obtains a signal having a 
waveform shown in FIG. 4(e) and feeds it to the VCO 72. The VCO 72 
compares the signal from the input terminal 71 with the signal from the 
flip-flop 74, and controls an oscillation frequency to be m times as high 
as the input frequency. Further, the output of the flip-flop 74 with a 
square wave having a duty ratio 50% as shown in FIG. 4(e), is supplied to 
the VCO 72 and the drive circuit 90. 
As described above, the PLL circuit 70 supplies the signal to the 
horizontal deflection circuit 80 and the drive circuit 90. The horizontal 
sync signal fed to the horizontal deflection circuit 80 has a frequency n 
times that of the horizontal sync signal contained in the television 
signal of the standard television system applied to the input terminal 10. 
Therefore, the horizontal deflection circuit 80 drives a horizontal 
deflection coil (not shown) at a horizontal scanning frequency two times 
that of the television signal of the standard television system. Further, 
the horizontal deflection circuit 80 is so designed that it operates at a 
frequency substantially n times as high as that of the television signal 
of the standard television system. 
Next, the drive circuit 90 adjusts an amplitude of a square wave with a 
duty ratio 50% formed by the PLL circuit 70 into an optimum value to be 
described later, and drives the auxiliary deflection means 100. The 
arrangement of the drive circuit 90 is the same as that of a usual 
amplifier and does not form the essential part of the present invention. 
Hence, no further explanation of it will be given. An example of the 
auxiliary deflection means 100 is shown in FIGS. 5a and 5b. In FIG. 5a, an 
auxiliary deflection means 101, a convergence magnetic device 102 and a 
deflection coil 103 are mounted to a CRT 104. The auxiliary deflection 
means 101 is comprised of a coil device. When current flows through the 
coil, a magnetic field is developed in a horizontal scanning direction to 
deflect an electron beam in a vertical scanning direction. FIG. 5b shows 
an arrangement in which auxiliary deflection means 105 and 106 comprised 
of electrostatic deflection electrodes are assembled into a CRT 107, and 
in the figure an electron gun portion is omitted. When voltage is applied 
to between the auxiliary deflection means 105 and 106, an electric field 
in a vertical scanning direction is developed to deflect the electron beam 
in a vertical scanning direction. Accordingly, when the drive circuit 90 
drives the auxiliary deflection means 100 with a rectangular wave current 
(or voltage), in synchronism with a period of the rectangular wave current 
(voltage) the electron beam is deflected in a vertical scanning direction 
proportional to the magnitude of the rectangular current (voltage) and in 
accordance with the polarity of the rectangular wave current (voltage). 
Though not shown, the auxiliary deflection means 100 may be arranged such 
that a coil is assembled into a deflection coil. 
A state of the scanning lines on the screen in this case will be described 
referring to FIGS. 6 and 7. Numerals in the drawings designate the numbers 
of the scanning lines. The scanning lines belonging to even fields and 
those belonging to odd fields are distinctively depicted by continuous 
lines and broken lines, respectively. Reference symbols (A), (B), . . . , 
in the drawing designate signals corresponding to the respective scanning 
lines of the NTSC system, which are television signals of the standard 
television system. The signals in the even fields are distinguished those 
in the odd fields by attaching primes to the latter symbols. 
FIG. 6a illustrates the relationship between scanning lines and signals 
when the signals of the NTSC system are displayed by a usual television 
receiver. FIG. 6b illustrates the relationship between the scanning lines 
and signals when the signals of the NTSC system are applied to the input 
terminal 10, in case where the drive circuit 90 and the auxiliary 
deflection means 100 are not used in the embodiment in FIG. 1. In the case 
of FIG. 6b, the frequency of the horizontal scanning is doubled, so that 
the number of the scanning lines is 1050. Since the number of the scanning 
lines is an even number, however, an interlace scanning is not performed, 
and hence the scanning lines of the even fields and those of the odd 
fields are superposed. Also, the arrangement of the signals, as will be 
clear, is such that the signals of the NTSC system are not exactly 
reproduced, as seen when comparing with FIG. 6a. This state, however, 
raises no particular problem. Nevertheless, an exact reproduction of the 
signals of the original NTSC system may be realized by means of a 
combination of the drive circuit 90 and the auxiliary deflection means 
100. The realization of this is illustrated in FIGS. 7a and 7b. In FIG. 
7a, a scanning line of the 2k th (k is an integer of one or more) of FIG. 
6b is located at a midpoint between its original position and a position 
of the (2k-1) th scanning line. This is realized by the drive circuit 90 
which responds to the signal shown in FIG. 4(e) to drive the auxiliary 
deflection means 100. In more specifically, the polarity of the signal 
shown in FIG. 4(e) is so selected that a signal portion corresponding to 
the 2k th scanning line provides a deflection direction opposite to the 
vertical scanning direction. Further, a magnitude of the signal supplied 
to the auxiliary deflection means 100 by the drive circuit 90 is set to a 
value capable of moving the scanning line by a 1/2 distance of the 
scanning line interval of FIG. 6b by means of the drive circuit 90. As a 
result, the number of the scanning lines are doubled compared to that of 
the original signal, so that an apparent resolution is improved and the 
arrangement of the signals allows a display of the exact arrangement of 
the original signals. While the above explanation is made to the method 
that the 2k th (i.e. 2k-th) scanning line is made to approach to the 
(2k-1) th scanning line by the half distance of the scanning line 
interval, the same effect may of course be attained by moving the (2k-1) 
th scanning line toward the 2k th scanning line. The same thing is true in 
the case that the (2k-1) th scanning line is moved toward the 2k th 
scanning line and the 2k th scanning line is moved toward the (2k-1) th 
scanning line respectively by a 1/4 distance of the original scanning line 
interval. 
In FIG. 7b, the (n-1) number of scanning lines succeeding to the 
(n.times.k-(n-1)) th scanning line are superposed on the (n.times.k-(n-1)) 
th one. In the case of the figure 7b, n=2. Therefore, the 2k th scanning 
line succeeding to the (2k-1) th scanning line is superposed upon the 
latter. In other words, the 2k th scanning line succeeding to the (2k-1) 
th scanning line scans the same path scanned by the (2k-1) th scanning 
line by the same signal. For realizing this, the polarity of the signal of 
FIG. 4(e) is selected so that a signal portion corresponding to the 2k th 
sanning line provides a deflection direction opposite to the vertical 
scanning line, and a magnitude of the signal supplied to the auxiliary 
deflection means 100 by the drive circuit 90 is set to a value capable of 
moving the scanning line by the distance of the scanning line interval 
shown in FIG. 6b, by means of the drive circuit 90. Through this process, 
the horizontal scanning frequency is doubled to thereby double the number 
of the scanning lines, however, the apparent number of the scanning lines 
and the apparent arrangement or distribution of the signals of FIG. 7b on 
the screen can be reproduced in exactly the same fashion with those of the 
original signals of the NTSC system shown in FIG. 6a. 
Let us return to FIG. 1. In the description thus far made, the television 
signal of the standard television system supplied to the input terminal 10 
is signal-converted and supplied to the CRT, and in displaying the signal, 
the scanning is made at the doubled horizontal scanning frequency. In this 
condition, the switches 130, 150 and 160 are connected in the state as 
illustrated. 
Explanation to follow is the operation of the television receiver when it 
receives a video signal of the second television system proposed by NHK in 
which the number of horizontal scanning lines is 1125, the horizontal 
scanning frequency is 33.75 KHz, and the vertical scanning frequency is 60 
Hz. In this case, the switches 130, 150 and 160 are switched-over to the 
positions located on the opposite side to those above-mentioned. A 
demodulator circuit 120, like the demodulator circuit 20, demodulates a 
video signal of the second television system supplied to the input 
terminal 110 into signals of three primary colors (the R, G and B signals 
in FIG. 1). The signals demodulated by the demodulator 120 are applied to 
the video output circuit 40, through the switch 130. 
A sync signal obtained by the demodulator circuit 120 is supplied to a sync 
separation circuit 140 which in turn separates a vertical sync signal and 
a horizontal sync signal from the supplied sync signal, as in the case of 
the sync separation circuit 50. The vertical sync signal is supplied to 
the vertical deflection circuit 60 through the switch 150. The vertical 
deflection circuit 60 is so designed as to operate at 60 Hz in a 
black-and-white receiving mode and at 59.94 Hz in a color receiving mode 
with respect to a usual standard TV signal system. Therefore, it can 
smoothly operate when receiving the signal of the second television 
system. 
An example of the vertical deflection circuit 60 is shown in FIG. 13. The 
circuit is a well known vertical deflection circuit and operates at 60 Hz 
in a black-and-white TV signal receiving mode and at 59.94 Hz in a color 
TV signal receiving mode. In the figure, reference numeral 61 designates a 
thyristor for the vertical oscillation, 62 a vertical sync variable 
resister, 63 a multivibrator for setting the width of the vertical pulse 
to a proper value, 64 a variable resistor for adjusting the vertical 
amplitude, 65 a vertical deflection coil. 
The horizontal sync signal is supplied through the switch 160 to the 
horizontal deflection circuit 80. The horizontal scanning frequency of the 
NTSC system is 15.734 KHz in color broadcasting mode and 15.75 KHz in a 
black-and-white broadcasting mode. Accordingly, the frequency of the 
horizontal sync signal obtained by the PLL circuit 70 is given by 
EQU 15.734(or 15.75).times.2=31.468(or 31.5)KHz. 
The frequency of the horizontal sync signal obtained by the sync separation 
circuit 140 is 33.75 KHz and the difference between it and the frequency 
of the horizontal sync signal obtained by the PLL circuit 70 is 
EQU 33.75-31.468=2.282 KHz. 
The frequency difference in this degree allows the television set to 
normally operate without switching-over or changing the high potential 
circuit constants at high potential portions contained in the horizontal 
deflection circuit 80, such as known resonance capacitor, the linearity 
coil and the S distortion correcting capacitor. If a synchronizing pull-in 
range of the AFC circuit in the horizontal deflection circuit 80 is set 
larger than the above frequency difference, the television set can receive 
signals of both the systems without switching-over the circuit constants 
in the AFC ciircuit. 
In this case, it is preferable that a free-run frequency of the horizontal 
deflection circuit 80 (a free oscillation frequency when no sync signal is 
supplied) is set at a midvalue between the horizontal scanning frequencies 
of the standard and the second television systems. 
An example of the horizontal deflection circuit 80 is shown in FIG. 14. The 
AFC circuit is comprised of a usual double-pulse type AFC circuit, and the 
horizontal synchronization is adjusted by a horizontal sync variable 
resistor 81. The pull-in range of the AFC is adjusted by changing the 
slope of a reference sawtooth wave or the pulse width, as well known. 
Reference numeral 82 is an oscillation transformer and the free 
oscillation frequency is set at any proper value by adjusting the core of 
the transformer. Reference numeral 83 designates a resonance capacitor; 84 
a horizontal deflection coil; 85 a linearity coil; and 86 an S distortion 
correcting coil. Reference numeral 88 indicates a transistor for 
controlling a voltage applied to a horizontal transformer 87. The voltage 
is set at a proper value by means of a variable resistor 89. The variable 
resistor 89 adjusts the horizontal signal amplitude. In order to secure a 
fixed picture amplitude for both the first and second television systems, 
a variable resistor 90 is connected in parallel with a resistor 91 by 
means of a relay (only its contact 92 is illustrated), thereby setting the 
voltage applied to the horizontal transformer 87 to an optimum value. 
In the above-mentioned way, the television signals of the standard and 
second television systems can be visually reproduced without 
switching-over the high potential circuit constants by means of a relay or 
switch etc. 
Turning now to FIG. 8, there is shown a block diagram of another embodiment 
of a television receiver according to the present invention. In FIG. 8, 
the portion for receiving the signals of the second television system and 
the changeover switches are omitted. The blocks with the same functions as 
in FIG. 1 are designated by like reference numerals. A different point of 
the embodiment of FIG. 8 from the FIG. 1 embodiment resides in that the 
function of a combination of the drive circuit 90 and the auxiliary 
deflection means 100 is executed by a rectangular wave superposed on the 
covergence signal. A convergence signal generating circuit 170 produces a 
signal for the convergence adjustment in a conventional TV receiver set on 
the basis of the signals obtained from the vertical deflection circuit 60 
and the horizontal deflection circuit 80. The amplitude adjusting circuit 
180 adjusts an amplitude of a rectangular wave with a duty ratio of 50% 
shown in FIG. 4(e) obtained by the PLL circuit 70 and then applies it to a 
superposing circuit 190. The superposing circuit 190 superposes the 
rectangular wave obtained by the amplitude adjusting circuit 180, on a 
signal for the correction of misconvergence in the vertical deflection 
direction, which is one of the signals obtained by the convergence signal 
generating circuit 170. The output of the superposing circuit 190 is 
amplified by the amplifier circuit 200 and used for driving the 
convergence coil (not shown). As a result, the signal obtained by the 
convergence signal generating circuit 170 corrects a misconvergence in the 
picture, as well known. As easily seen, the signal obtained by the 
amplitude adjusting circuit 180 executes the same function as that of the 
combination of the drive circuit 90 and the auxiliary deflection means 
100. In other words, an arrangement or distribution of the scanning lines 
and the signals, as shown in FIGS. 7a and 7b, may be adjusted by changing 
the amplitude of the rectangular wave shown in FIG. 4(e) by the amplitude 
adjusting circuit 180. The same function can be attained by a modified 
arrangement such that the convergence signal generating circuit 170 and 
the amplitude adjusting circuit 180 are digitally constructed, the 
superposing circuit 190 is modified for the signal adding or summing 
operation, the amplifier circuit 200 is modified for the D/A conversion 
and amplifying and an output signal from the amplifier is used for the 
convergence coil. 
FIG. 9 shows a block diagram of another embodiment of a television receiver 
according to the present invention. In FIG. 9, the portion for receiving 
the television signal of the second television system and the changeover 
switches are omitted. Further, the blocks with the same functions as those 
in FIG. 1 are designated by like numerals. A different point of the 
embodiment of FIG. 9 from the embodiment of FIG. 1 is that the function of 
the combination of the drive circuit 90 and the auxiliary deflection means 
100 in FIG. 1 is executed by a rectangular wave superposed on a vertical 
deflection signal of the vertical defleciton circuit 60. More 
specifically, an amplitude of a rectangular wave of the duty ratio 50% 
shown in FIG. 4(e) obtained by the PLL circuit 70 is adjusted and supplied 
to the vertical deflection circuit 60, and then is superposed on the 
vertical deflection signal. The arrangement of the scanning lines and the 
signals as shown in FIGS. 7a and 7b can be adjusted by adjusting the 
amplitude of the rectangular wave to be superposed on the vertical 
deflection signal, shown in FIG. 4(e). 
FIG. 10 shows a block diagram of another embodiment of a television 
receiver according to the present invention. In the figure, like numerals 
are used for designating like blocks in FIG. 1. A different point of the 
present embodiment from the embodiment in FIG. 1 resides in a signal 
converting circuit 210 and a luminance setting circuit, and no provision 
of the drive circuit and the auxiliary deflection means. 
The operation of the signal converting circuit 210 will be described 
referring to FIG. 11. A waveform in FIG. 11(a) is that of one of the 
signals obtained by the demodulator 20, and this signal is applied to the 
signal converting circuit 210. The signal converting circuit 210 includes 
two memories and operates as shown in FIGS. 11(b) and 11(c). As shown, 
when one memory is in a write mode, the other memory is in a read out 
mode. Those operation modes are inverted every horizontal scanning period 
of the television signal of the standard television system. The signal 
written is read out once at a speed two times the writing speed, in the 
first half of the next one horizontal scanning period. Accordingly, a 
signal of FIG. 11(d) is read out from the memory operating as shown in 
FIG. 11(b) and a signal of FIG. 11(e) is read out from the memory 
operating as shown in FIG. 11(c). A signal shown in FIG. 11(f), as the sum 
of the signals of FIGS. 11(d) and 11(e), is supplied, as an output signal 
from the signal converting circuit 210, to the luminance setting circuit 
220. 
The signal FIG. 11(f) supplied from the signal converting circuit 210 to 
the luminance setting circuit 220 exists only for 1/2 (1/n) period of one 
horizontal period of the standard television system, when compared to the 
original signal of FIG. 11(a). Accordingly, an average luminance in the 
picture when the television signal of the standard television system is 
displayed and that when the television signal of the second television 
system are related by 1:2 (1:n). In order to make the average luminances 
for both the television systems equal to each other, amplitudes of the 
signals supplied to the video output circuit 40, therefore, must be 
related by a ratio of about 2:1 (n:1) by means of the luminance setting 
circuit. 
FIG. 12 illustrates that an interlace relation of the origianl signals can 
be exactly reproduced when the televison signal of the standard television 
system is displayed by the embodiment of FIG. 10. 
In FIG. 12, scanning lines in an odd field is indicated by continuous lines 
and scanning lines in an even field by broken lines. Symbols (A) and (B) 
designate signals corresponding to scanning lines of the television 
signals in the standard television system shown in FIG. 6a. The reason why 
no even number th scanning lines are illustrated is that the portions in 
the picture corresponding to the even number th scanning lines have no 
signals, as shown in FIG. 11(f). As seen from the figures, even if the 
drive circuit 90 and the auxiliary deflection means 100 as shown in FIG. 1 
are not used, the original television signals of the standard television 
system can correctly be reproduced free from the superposition and 
irregularly interlacing of the odd and even fields, as shown in FIG. 6b. 
In the case of FIGS. 11 and 12, the read out operation is made in the 
first half of the horizontal scanning period so that a signal is read out 
from the memory at the time of the odd scanning lines, and no signal is 
provided at the time of the even scanning lines. Alternatively, if the 
read out operation is made in the latter half of the horizontal scanning 
period, the signals corresponding to the even and odd scanning lines are 
made in the reverse relation. In the case, when the odd scanning lines 
appear, no signal is provided. 
As described above, the television signal of the standard televison signal 
is converted into a signal with an n times horizontal frequency. When 
receiving the television signal of the standard television system, the 
horizontal deflection circuit operates at the n times horizontal scanning 
frequency. When receiving the television signal of the second television 
system, it operates at the horizontal scanning frequency of the second 
television system. Accordingly, there is no need for switching the high 
potential circuit constants in the deflection circuit. The memory capacity 
needs memories only for two lines. Therefore, a television receiver with 
good reliability and a simple construction can be realized. 
Further, the television set according to the present invention has a 
function to move in the vertical scanning direction the scanning lines at 
the horizontal scanning period of the standard television system and to 
adjust the scanning line interval properly. Accordingly, it can display a 
picture with a correct arrangement of the scanning lines and the signals.