SU641675A1 - Method of transmitting and receiving colour television signals - Google Patents

Description

36 through a 90 ° phase shifter, circuit 5 is connected to the modulator 6. A second signal sensor 7 is connected to the control input of the modulator b, and the inverter 8 is connected to the modulator 9, and directly to the modulator 9. The output of the sensor 10 of the third signal is connected to cyivtt-iaTopaM 2 and 1. To the second input of the adder 11 through the phase inverter 12 is connected the sensor 1 of the first signal. The output of the adder 11 is connected to the modulator 13, the high-frequency input of which is connected to the generator 14 of the second carrier frequency. The output of the generator 14 through the phase-shifting circuit is not connected to the modulator 9. The outputs of the modulators 3, b, 9 and 13 are connected via a slide 16 and filter 17 to the antenna 18. The receiver (figure 2) contains an intermediate frequency amplifier 19 (IFA) The output of which is connected via the notch filter 20 of the first frequency to the generator 21. The output of the generator 21 is connected to the synchronous detector 22, the second input of the synchronous detector 22 is connected to the output of the ASF 19 through the notch filter 23, the output of which is connected to the generator 24. - - ,, - The output of the generator 24 is connected to the input synchronous house 2S detector, another input of which is connected to the output of the detector filter 20. The outputs of the synchro detectors 22 and 25 are connected to су1 ®; 5 directly 26 a / a. Ftutor 2 is a synchronous detector 25 through the phase inverter 28. The IFC 19 output is connected to video detector 29, the output of which produces only the third signal. The device works as follows. As the first signal, the signal of the blue color-separated image 55 U-g is used, and the signal of the red color-separated image Uij is used as the third signal - the negative signal & h: e of the capacitive signal U. B pen of the atchake (figure 1) formz ruets - with gnal5 W - V rt I e P-H9. Y, f, .. th j) t-, a) - | - sinCuj, tSti H- U2 os isi at- 4S ") - | iUgi (COs (aj2-SgH + yy Sl" yU2-Sl H-- U C05 {M.) Ga) t where W is the first carrier frequency f tSJg, is the second carrier frequency. The first term of the expression (1) is formed in the adder 16 when the orthogonal components of the first carrier frequency arrive (sa from generator 4 through modulator 3 directly (coj t) with a shift of 90 ° through the phase-shifting depot 5 and modulator 6 (). The second and third terms of the image in modulator 3 when exposed to an adder signal (J formed in adder 2, to the input of which the negative signal UY is received from the sensor 10 and the signal Ug comes from the 1 p sensor. Lower side band of amplitude no-mo The duplicated signal is filtered in filter 17. The fourth component of the BG trap (1) is formed in the modulator b when an input signal U, formed by sensor 7 and inverted by a power inverter 8, is applied to the input (Phase of the carrier oscillation from generator 4 is shifted by an EO phase-shifted circuit 5 on the EO Thus, at the output of the modulator 6, a sinusoid (the fourth term) is obtained. The fifth term is formed as a sum (cosuugt sintDgt) from the signals of the carrier oscillator 14, fed to the adder via the modulator 13 directly (cosWgt) and through fa osdvigayuschuyu circuit 15 and a modulator 9 Cu displaced by 90 ° (in W t sixth and eighth terms are formed under the action of the sum signal (.), the resulting. , "," It. u-GV V- - f tJ, -wJ J H-rit j, in cyfJSMaTope 11, to the carrier frequency (uoswjgt) in the modulator 13. The seventh term is formed in modulator 9 when the second signal {k UR) acts on a sinusoid ( 5 | пw i). For severity, it is necessary to take into account their magnification 12 times as a result of appropriate summation, and (COSCW t + SinoD t) Tf2 U {cos (4S °) ("u, t- -45 °) B in the receiver (fig .2) notch. The filter 20 selects the first carrier frequency W, which phases the local oscillator 21, whose oscillations are reference for the synchronous detector 22. Strictly speaking, the oscillator 21 must contain a phase-shifting circuit of 45 ° at the input. Then, at the output of the generator 21, a sinusoidal carrier oscillation and sin) is formed. By multiplying the source signal (1) by U sinou t at the output of the notch filter 20, we obtain, UoC.t)) t - VI-UgksinSlgt + U sinfflt-i4S °) U 1cco6Sl t-sin (t9j2-WiHt45 Ug-k5iti (ou2- UJ -Sig) i + - Uj kcobCtUa-i i-Sl H -% - jU 5inr (uj2 -., - aH-v46 °. (2) If this signal (1) is multiplied by UgS-inuy t, then by the output of the notch filter 23 is obtained. f Un (, tl5finaj ,, t - -5-in (LLij-UJ H-45 ° j +

(, -ng-) t-- UySiK (aJi f

t .uu -ait-4S ° - Uf, -kcos (uu2-ii-si - t yiVI - U ksin "t UjcosR tB

2 R J2-u 6inCfti-45) 4 1 in cyMiviaTope 26, expressions (2) and (3) are summed up and at C U - UQ we get "l -§ - fB BTB () tt-- TnUYC05Slt-: C05 (UU2 -ija H -f2U co (w., i.e., a separately separated, sintered signal and the same signal by often tsUp I, since the growth signal is transmitted with a shift of 45 ° with respect to the signal of blue and red color-separated image ratio, then the ratio of amplitudes of the output and luminance signals is violated. In view of this, the compression ratio of color signals i “1/1/2“ o, 708 has been introduced in the adder 27, taking into account the signal inversion in the phase inverter 28, signal and j.Cf -T and R a dt + .ShV2 U 5irtKt. In the video detector 29, only the luminance signal is selected. Thus, the proposed method compared to the known provides transmission of chrominance signals without using the subcarrier frequency, distorts the image to the torus. transmitted without quadrature distortion. This method allows

641675, 6

get a three-fold reduction in the frequency range of the transmitted signals.

Claims (1)

The method of transmitting and receiving color television signals i consisting in quadrature modulation of the first color carrier frequency w with two color signals with simultaneous frequency modulation of the first color carrier sound signal, characterized in that in order to reduce the frequency band of transmitted signals as color, and a black and white image, transmit a blue color separated image signal in positive polarity and a red color separated image signal to a negative field on the first color carrier frequency R4 and at the same time the same signals in the opposite polarity are transmitted on the second color carrier frequency Wg located on the opposite edge of the frequency range, while the luminance signal in negative polarity is transmitted on the two specified 4j w points ., and uj with a shift of 45 ° with respect to the quadrature modulated components of the color signals, and when receiving, there is a separate synchronous separation of the signals transmitted on the two carrier frequencies W and jLi with the subsequent summation and subtraction of the selected signals. Sources of information taken into account in the examination. 1. Pevzner B.M. System 1 "and color television energy, p. 25