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Rohde & Schwarz 230.8518, Manual

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Rohde & Schwarz 230.8518 Manual Download Page 35

G0

003

-

nonoeascnwmz

STEREOCODER

GO 003

for the

most

exacting requirements

(channel

separation

:

60

dB);

generates

a

stereo

multiplex signal according

to

CCIR,

EBU

and

FCC

recommendations

(pilot-tone system)

to

modulate

transmitters

Data

sheet

N

3

-

297

E71

Summary of Contents for 230.8518

Page 1: ...M SCHWARZ ther uh 43 3 an Egmcwb 0 5 3th MANUAL STEREOCODER GO 003 230 8518 mammmz co mszfimmhmnb owfianQQmM w a an AR ...

Page 2: ...ief Operating Instructions 9 2 4 Operation 9 2 4 1 L and R input 9 2 4 2 MPX l and MPX 2 Outputs 10 2 4 M Output 11 2 4 4 Stereo Mono Switchover 11 2 4 5 Pilot Tone 12 2 4 6 Auxiliary Inputs l3 3 Maintenance 14 3 1 Routine Maintenance 14 3 2 Checking the Rated Specifications 14 3 2 1 Required Measuring Equipment 14 3 2 2 Measurements l4 4 Circuit Descrigtion 17 4 1 L and R Channels 17 4 2 Coder 17...

Page 3: ... oo oo co ooaanoo cu oooo Iainooao oouc oooono uoa no ona ooooo a o ooan IIIOIICDIDIOIIIIOIIIDIIIOIIO 5 3 3 Indication 5 3 4 Channels L and R c no ooooon ooogno IJ olouo 5 3 5 MPX Lowpass Filter and Output Amplifier 5 3 6 Pilot tone Generation 5 3 7 Crosstalk L R 5 3 8 Crosstalk M S Interior view Pin assignment 1 2 3 Fig 4 Preemphasis 5 Level diagram 6 Front and rear panel controls Oscillograms Pi...

Page 4: ...sted internally LED _2_is on for Q off and R L L Ra_ndL R Attenuator switches for common level adjustment of the L and R channels in steps of 3 dB 2 0 5 dB 2 and 0 1 dB 5 Pushbutton for switching on and off the preemphasis change soldered links for 50 or 75 us LED 1g signals when preemphasis is switched off Panel meter with the following two scales 0 dEm 0 775 Vrms 15 to 8 dEm for L R and MPX sign...

Page 5: ...e following positions 0 no pilot tone in the MPX signal LED lg signals pilot tone is adjustable with g amplitude and 9 phase LED lg signals pilot tone with standard level and standard phaSe available in the MPX signal LED lights when pilot tone is missing or not to specification when the inputs or the preemphasis are switched off 13 MONO Pushbuttons with pilot lamps for mode selection MONO both ch...

Page 6: ...th label indicating the selected AC supply voltage Multiplex outputs fed by separate amplifiers Mono centre signal output Left channel input Right channel input Male connector strip with pin assign ment according to Fig 3 Terminals 1g to 22 are in parallel with those on the male connector strip 2 2 Pregaration for Use See Fig 2 2 2 1 Adjusting to Local AC Sugglx The GC 003 is factory adjusted for ...

Page 7: ...n be adjusted up to 4 k9 For Rin 600 Q R138 R159 700 9 2 2 4 Chaggihg to Operating Mode MONO For the transmission of monaural signals the stereocoder can drive both channels from one input Eithatthe left or the right channel must be set by a link the channel will then feed both multiplex outputs in the mode linked a MONO Insert the link 2810 into L for the left channel and into R for the right cha...

Page 8: ...c R 9abc see Fig 3 The inputs may be balanced or unbalanced The input voltages must be free from any DC component to avoid DC magnetization of the transformers Channel L EulO gg Sthl Oab c 23 Channel R EuEO 2 Sthl 9ab c Input selection Switch l permits the above inputs to be switched on and off as well as the signal from the built in AF generator to be applied for checks and measurements Level adj...

Page 9: ...ltage by 13 6 dB at 15 kHz Thus the maximum input voltage AF should be no more than 1 dEm in order not to exceed the overdrive limit of l2 5 dEm In the case of 75 us preemphasis the maximum input voltage is 4 5 dEm Signal indication The level of the left or right channel can be observed on the upper scale of meter 6 with switch 7 in position L or R The measurement range can be extended by 10 dB wi...

Page 10: ... of meter é Note for measurements with discrete frequencies The output voltage is obtained by adding the L and R signals after the pre emphasis sections This causes an increase of 13 6 dB at 15 kHz when the preemphasis is switched to 50 us and of about 17 dB with 75 us A deemphasis section compensates for this increase so that a flat frequency response is obtained The overload limits such as menti...

Page 11: ...e control 2 AU and adjustable phase control 19 aq added to the multiplex signal Pilot amplitude adjustable in the range 16 dBn to 5 dEm relative to the 6 dEm level of the multiplex signal Pilot phase adjustable in the range 50 to 50 compared with the standard phase with respect to the 38 kHz sub carrier Indication If the indication selector 1 is in position PILOT the pilot level can be read on the...

Page 12: ... peak to peak pull in range approx f2 Hz 2 4 6 Auxiliary Inputs The three auxiliary inputs can be used as follows Nominal level SCA signal Sthl 50 6c 30 Hz to 7 5 kHz 10 to 12 dEm Traffic radio signal Sthl 4a 4c 53 to 100 kHz 14 dEm Additional signal Sthl 4b 4c 53 to 100 kHz 10 dEm Contacts 4c and 60 chassis screen I The SCA channel can only be used when the SCA modulator is built in ror this purp...

Page 13: ... 10 MHZ TEKTRONIX high overload capability for measurements of cross talk in multiplex signal AF analyzer or bandwidth 100 Hz FAT 2 selective AF volt sensitivity better than meter 70 dBn Stereodecoder MSDC 2 Psophometer contained in SUN 2 U Distortion meter e g LEA or HP 5 2 2 Measurements Refer to the data sheet for the required results Checking the amolifier characteristics Apply a signal to the...

Page 14: ...z to 15 kHz 6 dEm L R Preemph off Deemph in L R L R L R decoder off Referred to 500 Hz Preemghasis 500 Hz 15 kHz 6 dEm L R H H lj 6b dB BOus Preemph on 17 07 dB 75 s t0 2 dB Deemph in decoder off Pilot level L o R o Bu4O MPX Pilot on or AkpAU J10 MPX 32g 3_scale Indication 500 HZ 6 dBm Pilot off L R L R L R L R upper scale L R L R lower scale R 38122 15 ...

Page 15: ...s fl 13 kHz and f2 14 kHz Adjust the same level on both generators to that the meter J1 indicates 6 dEm or l2 5 dEm Measure the amplitudes at the corresponding decoder outputs fl V1 13 kHz f2 V2 14 kHz 2fl f2 81 12 kHz 2f2 f1 SE 15 kHz f2 fl D 1 kHz If the distortion is 10 the intermodulation distortion components may be calculated in accordance with DIN 45403 as follows D _ 51 32 2 V1 V2 d d 3 _ ...

Page 16: ...ts the channel associated with mono operation The amplifier T111 to T116 which has a two stage feedback circuit feeds the L Rm 31 150 and St101 8abc by means of transformer TrlO The deemphasis section R206 C141 in the feedback path is switched with 8105 sum outputs M and cancels the preemphasis in the left and right channels 4 2 Coder See circuit diagram 230 8518 8 sheet 2 and oscillograms Fig 6a ...

Page 17: ... the pilot generator circuit see section 4 4 c Correction signals for reducing the crosstalk via R265 0146 and R264 0147 lines A and B Interfering switching spikes 532 kHz from the coder are eliminated by the sample hold circuit T137 0155 The emitter follower T138 whose resistor is designed as a constant current source comprising T139 feeds the MPX low pass filter Via line J The MPX lowpass filter...

Page 18: ...vailable for the shift register From this frequency the monostable circuit consisting of T141 T142 obtains the slightly delayed sampling pulses for the sample hold circuit T137 in the summing amplifier The stages 1 to 14 in the 16 digit shift register B108 BlO9 are connected Via 3109 12 G1 107 B108 7 so as to form a ring One bit continuously cycles with the clock frequency and thus causes a high l...

Page 19: ...able pilot tone mode there is no output in the pilot mode off The PLL IC B114 provides external synchronization of the pilot tone via the input Sthl 3a It compares the offset between the internal pilot frequency at pin 3 and the external pilot frequency at pin 14 and then delivers a DC voltage which is proportional to the phase difference With appropriate set ting of link BRTO4 this DC voltage is ...

Page 20: ...th 820 The halfwave peak rectifier circuit using T117 to T120 evaluates the negative halfwaves of the input signals L or R The differential amplifier Tll9 T120 delivers the signal for the transistor T118 which operates as a rectifier Capacitor C143 is charged to the peak value The FET impedance transformer T117 delivers the indicating voltage for meter J10 while offering a minimal load for the cha...

Page 21: ...STlO through the noise filter X10 the power switch 310 and the fuse Sil to the power transformer The two secondary windings feed the control circuit YlO Lamp R1 10 indicates that the unit is switched on The board YlO is made up of two identical regulator circuits for the 12 V and 12 V output voltages The feedback amplifier B401 E O2 controls the series transistor T401 T402 resistor R401 R402 limit...

Page 22: ...e input selector 8101 to position R L and check the level with the indication selector 8106 in positions R L and R L The indication must be 6 dEm in both channels In case of an error carry out further checks according to the level diagram in Fig 5 test points MPlOl to 108 MPlll links BRlOl to 103 5 2 Generation and Processigg of Pilot Tone Set the indication selector to PILOT and check for the cor...

Page 23: ...mV at St402 6 7 Adjust R411 for 12 V f50 mV at St402 l 2 chassis St402 4 5 5 3 2 AF Generator Fit the resistors R181 and R182 on solder terminals according to the desired frequency set in factory to 500 Hz Frequency 1 kHz 48 7 kg 15 8 kg Set the input selector 8101 to position L or R Measure at test point MP109 with distortion meter voltmeter and frequency counter Adjust R187 for minimum distortio...

Page 24: ...nputs EUlO and EUEO with a level of about 6 dEm at the specified pole frequencies t0 5 and adjust for minimum at test point MP Pole frequency Left channel Right channel 38 8 kHz 19 2 kHz L106 18 1 kHz MPIO4 L107 MPlO8 23 1 kHz L108 Carrier suggression Measure the DC voltage offset on B103 and BlO Set link E8101 to L and ERlO2 to R do not apply an AF signal Adjust R135 for O V to 5 mV at test point...

Page 25: ...tion Crystal oscillator Measure the frequency at test point MPlO9 link 3R104 being set to J as set in factory Adjust to 4 256 MHz 21 x 10 5 with R317 Pilot indication Set the indication selector 8106 to PILOT and the pilot mode selector 5107 to on Adjust for 9 5 dBn indication on the lower scale using R314 Pilot amelitude Set the indication selector 8106 to PILOT do not apply an AF signal Measure ...

Page 26: ...sure the voltage VPH Check the setting range available when using R316 WAQ VPHshould be varied symmetrically by t8O mV This corresponds to a phase setting range of approx imately f5o referred to the above mentioned levels AF voltage 16 dEn pilot level 9 5 dEm If the Setting range is extremely asymmetrical vary R315 so that VPH 10 mV when R316 is at its mid position Distortion of jB kHz subcarrier ...

Page 27: ...e with an AP signal Connect BUlO 2 and EUlO 3 transformer screening to chassis Channel L EUIO Channel R BUEO Crosstalk 5 3 8 Crosstalk M S Switch off the pilot mode 8107 and the preemphasis 8105 Measure at the multiplex output EU40 with a selective AF voltmeter Drive both channels simultaneously with 6 dEm The attenuation referred to the input level must be attained at the specified test frequency...

Page 28: ...20 21 22 23 O Fig 1 FRONT and rear panel controls SCA MUD OPTION Ehunge over BR1U7 STHU BR103 3 BR105 ans BldstlOIQI QtotolnmUninio unamcop unnoqwnynvuvann auto v 00 M zw i g y 0 i Q 0 RIM R182 BR10L AF generator Pilot int ext Fig 2 Interior View 1 2 ...

Page 29: ...4381 oxna ISIIBJBd 1nd zufita ogre Ietteled w 1nd1no a vq oéna ovna oz IaIIBJBd 1ndzno leN mdzno zxaw Ieufigs oaxags zndut vos 211219 ouo T N a n terms Iwomppv Hv q l Ieufits 01pm 013 18 fibr o 1 0 33 1nd1no WUd 11 c a I 1min qond 4x3 _ o E oncuzoa ouow 3 I 10 141103 03 1345 z q a o f D a reufizts ouou A bl 3 eufixs 03 1919 ________ J ...

Page 30: ... a m lllll 3 55 3 Ho on omaza oohaaw Ilul 33 fig 0 02 B E 5 00 3 5 6 62 a I m _ E m Ez 9E2 N 33 E q 32 H _ e _ 3 Ho 25 25 Ma filmIOumflm DEE iii A _ 33 23 um lv lllll 3m KGB SE 801 55 50 5 0 Emumn E 2 3 5382 IL E 388 5 a I I Hazmflm 3mg 3 8 933 3 0 x 4 4593359 xmom a 1 gram Level d Fig 5 R 38122 31 ...

Page 31: ...to coder B107 11 a 14 1 sz 10 v 1 8107 10 1 9 13 I 1 8107 4 l 10 12 I I I 8107 3 I 11 J I 1 8108 7 I J I Data Bit 3 1 1 1 5 1142 12275 6 b R 333 341 8 a a 1 91 Pilot A1 0 B113 11 l l l S107TQ ST 101 3b MP115 A J 8112 8 6 6 6 fl 8112 11 7 I 1 P1101 4319 5 S107za1p AU B113 1 1 157101 313 1 1 MP 115 11 Edge of trigger pulse for ascilloscope Flg 6 Oscillograms Pilot tone generation R 38122 32 ...

Page 32: ...1 7a 7b 7c 7d Pilot tone R 38122 83 MPHB Input level 6 dBu vpp 2 3 x 1 55V 4 3 64 dB 2 73 ans 72 dB 1 oa aVss 10 times overload i e one division approx 7 3V Qscillograms C Oder circuitry ...

Page 33: ...Pilot phase Pilotton Pilot tone Pilottonausgang Pilot tone output Pilottonerzeugung Pilot tone generation Quarzoszillator Crystal oscillator R 138 und 139 nur bei Bedarf R 138 and 139 only used if necessary R _ Eingang R input Regelteil Power supply Spitzenwertanzeige Peak indication Spitzenwertgleichrichter Peak rectifier Stereomeldung Stereo signal Stereorelais Stereo relay Stromversorgung 12 V ...

Page 34: ... Zusatzeingang Additional signal input Zusatzsignal Additional signal H 15 kHz Tiefpasse lB kHz lowpass filters R 38122 55 ...

Page 35: ...EREOCODER GO 003 for the most exacting requirements channel separation 60 dB generates a stereo multiplex signal according to CCIR EBU and FCC recommendations pilot tone system to modulate transmitters Data sheet N 3 297 E71 ...

Page 36: ...ed multiplex outputs are provided on the Stereocoder GO 003 to meet the requirements of use with transmitters For checking purposes the GO 003 is equipped with a high grade L Ft floating output for the M Signal The sensitivity of the AF inputs can be accurately matched to the input levels by means of step switches over a wide range The built in AF oscillator produces a 500 Hz signal of high ampli ...

Page 37: ...evel attenuator Further signals in the range between 53 kHz and about 100 kHz e g traffic radio SCA channels can be added without affecting Rear view GO 003 STEREOCODER GO 003 the multiplex signal An optional SCA modulator can be fitted in the Stereocoder by removing a shorting plug The modulator consists of eight electronic switches After adding the pilot tone the multiplex signal MPX from the mo...

Page 38: ...IONS GmbH Co KG D BOOO Miinchen 80 Miihldorfstr 15 Tel 089 4129 1 Int 49894129 1 Telex 523703 OHDE SCHWARZ Printed in the Fed Rep of Germany Subject to change Data without tolerances order of magnitude only 680 U ...

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