ASTEC A BSR COMPANY

DESCRIPTION

The UM1285·8 Is a high performance Intereamer Vestigial Sideband Modula· tor which Is primarily Intended for use In color TV games, VTR's, computer graphics, Teletext and view data adapt· ers. The UM1285-8 has a very linear trans· fer characteristic which ensures a good grey scale, controlled chroma levels and freedom from sync compression with Its associated frame and line Jitter problems. Good subcarrler Intermodu· latlon performance minimizes the on·screen bar pattern due to chroma and sound subcarrler beats.

FEATURES:

D Compact and Low Profile.

D Rugged and Stable.

D Good Modulation Linearity.

D Low Chroma/Sound Beat Product (55dB Typical).

o Pretuned Vision Carriers CH3, CH4.

o Pretuned Sound Subcarrler 4.5MHz.

o Pretuned Vestigial Sideband Filter.

D Bullt·ln Voltage Regulator.

D Negative Transfer Characteristic.

o Low Radiation (FCC Approvable).

D For Color Application.

D 75 Ohm Output from a Standard Phono Socket.

D Designed for PCB Insertion.

Uhh i285·8 VHF Intercarrier Vestigial

Sideband Modulator

-.

ABSOLUTE MAXIMUM RATINGS:

Applied voltage between Pin 1, 3, 4, and Case (See Pin Connection) should be from - 3.0V to + 15V. .

Applied voltage between Pin 3 and Case should be from - 3.0V to + 8.0V. (Refer to Table 1 for higher voltage appl ication.)

Operating Temperature Range = O·C to +45"C.

Storage Temperature Range = -20"C to + 70·C.

CHARACTERISTICS

The UM1285·8 Is designed to operate over a supply voltage range of 6V to 15V. A bullt·in 5.0V voltage regulator Is provided to achieve excellent stability against voltage change. An external series resistor is required on the supply voltage input for current limiting purposes. Table 1 shows the value of the series resistor required for various supply voltages.

Modulation occurs when a positive going voltage Is applied to the video input pin. The transfer characteristic is negative (See Graph). As a result, a positive going input causes the RF output to decrease. Peak RF output is specified when the video input is at 2.2V.

The user can select between CH3 and CH4 operation by switching the Channel Select Pin to ground (OV) for CH3 or to an open circuit for CH4.

Supply Voltage Vce Volt 6.0 7.5 9.0 12.0 15.0 Series Resistor Rs Ohm 0 47 100 160 270

Table 1: Series Resistor with respect to supply voltage.

FCC APPROVAL

The UM1285·8 is FCC approvable due to Its very low radiation, stabil ized carrier oscillators, and vestigial sideband filter which ensures that all sideband components outside FCC limits are greater th~m 30dB down.

NOTE:

To use the UM1285·8 In the USA, It Is absolutely mandatory that the finished product using this device, in Its finai production form, first be submitted to the FCC for testing and certification under the 'TV device, Class 1.' classification.

AC Coupled InpuC

DIGITAL

______ ,-__ -.J

L-_--' _______ _

TYPICAL SOUND liP SETUP

TEST CIRCUIT

CH3 CH40

o-_------~ SOUND \

Vrx o---r-"l--=Rs:"'-'---1 SUPPLY ) UM 1285·8

TYPICAL INPUT WAVEFORM

5V pop

_--+MAX

DC Coupled InpuC

TYPICAL MODULATION INPUT VOLTADE SETUP

TYPICAL APPLICATION

eH4 CH3

SO UNO +12V 1

At

2.88V

.12V 1800

r------.--4Vl0EOMOD I ~O.O1~1 180 0

210SV V

NOTE:

1.5M

SPECTRUM ANALYZER

1. In case of testing with 500 liP spectrum analyzer. matching p8d of 751500 (A TTEN 10dB) should be employed.

2. Standard AF coaxlaf cable should be 1.5M long 8nd 750 characteristic Imped8nce.

-iI- I - . ~

-if 'l-

II -it-

-i' 'I-

MOSCH.P 50 pI

RECOMMENDED PCB HOLE CENTERS (COMPONENT SlOE) (millimeters)

(1) (2) (3) (-4)

LEAD FUNCTION

1 Composite Video Input (VMOO).

2 Supply (Vee).

3 Audio Input (VSMOO).

4 Channel Select.

Case Ground.

'U+'I t +++f.' r i l~.("LCS) 66.2 -tJ--312-~

L 4.5X1.5 (4 PlCS.)

.:p

UM 1285-8

1 -y TOlV

RF output LOAD = 75 Ohms

SYMBOL DESCRIPTION

Fe CH3 Video Carrier @25°C

Fe CH4 Video Carrier @25°C

F,se Sound Carrier @25°C

Vo(HI) Video Carrier Output (VMOD = 2.2V)

Vo(LO) Video Carrier Output (VMOD = 2.8V)

Vose Sound Carrier Output

Vs Spurious/Harmonic

VSWR Voltage Standing Wave Ratio (CH3 and CH4)

6Fc{T) ~F for change in temp

6Fse{T) 6F for change in temp

~Fc ~F for 1 Volt change in Vee

~Fse ~F for 1 Volt change in Vee

Zo RF Output Impedence

RFBW - 3dB Bandwidth (RF) CH3 CH4

Icc Supply Current

6F/:1V Frequency Modulating Sensitivity

920kHz Chroma/Sound Beat Level

ZIN Video Input Impedance

TYPICAL TRANSFER CHARACTERISTIC

1.0

.8

B-e u. a: .6 o w N ::;j « ~ .4 II: o Z

.2

MIN TYP MAX UNIT -61.00 61.25 61.50 MHz 67.40 67.65 67.90 MHz

4.480 4.500 4.520 MHz 0.8 1.5 2.5 mVRMS

14 18 - dB w.r.t. Vo(HI)

26 22 18 - dB w.r.t. Vo(HI)

30 - dB W.r.t. Vo(HI)

1.7 2.5

±10 kHzrC ±750 Hzl°C ± 30kHz kHzlV ± 5kHz kHzlV

75 Ohm

10 14 MHz 4.5 5.0 MHz

30 40 mA 4.0 8 12 kHzlVolt

48 55 - dB w.r.t. Vo(HI)

See Modulation Transfer Characteristic

TYPICAL BANDPASS FILTER RESPONSE

·12dB

_I

PHONO SOCKEl

RF OUTPUT:SOCKET (millimeters) .

1-9.5

LI TYP •

.-~.175TYP. ·

. TYPICAL PHONO PLUG STANDARD TEST PIN

. The modulator shall completely accept a standard test pIn; u an assurance against excessive solder, etc. blocking up phono socket.

OUTLINE DRAWING FOR UM1285·8 (millimeters)

• -Fltl'i

21 MIN.

71 MAX.

L~ u-1~

20 MAX.

STANDARD PACKING 225 units in a shipping carton Shipping Carton: Gross Weight: 40 Ibs. or 18 kg Size: 12x18x16 In. or 30x45x40 em Volume: 2 cu. ft . or 0.054 cu. m.

2 /85 Printed in U.S .A .

. ('/.///> ASTEC A BSR COMPANY

(1) (2) (3) (4)

I

ASTEC USA 2660 San Tomas Expressway. Suite 200 Santa Clara, CA 95051 U.S.A. TEL. (408) 748·1200 TELEX: 474 ·5018 ASTEC UI FAX: (408) 727·8281

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