zhc518a-50w~300w tv transmitter user's...

www.fmuser.org

www.fmuser.org

1

FU-300W

TV Transmitter

User’s Manual

www.fmuser.org

www.fmuser.org

2

Please notice this：

1. Read safety notice first.

2. A 50 Ohm dummy load or antenna and cable must be connected

before turning power on, avoiding water going into the connecters or

the cable.

3. Please read System Control Logic section to fully understand how

the system works.

4. Please read the Power On Sequence.

www.fmuser.org

www.fmuser.org

3

Contents

Safety Notice

1. Overview --------------------------------------------------------------------------------5

2. Technical Specifications --------------------------------------------------------------5

3. System Structure and Function------------------------------------------------------6

4. Test Instrument-------------------------------------------------------------------------7

5. Test and Maintenance -----------------------------------------------------------------8

6. Panel Function Description ---------------------------------------------------------8

7. Power on Sequence -------------------------------------------------------------------9

8. System Control Logic-----------------------------------------------------------------10

9. Direction for Operate and Display ------------------------------------------------10

10. Indicator light-------------------------------------------------------------------------2

11. Failures Check ----------------------------------------------------------------------2

www.fmuser.org

www.fmuser.org

4

Safety Notice

1. Please read the following safety points, in order to avoid the accidents and prevent the

connecting machines to be broken.

2. Only the qualified maintenance workers can operate the service.

3. Prevent the fire and the bodily injury.

a. Use the proper wire. If not, it will cause the fire and the bodily injury;

b. Ensure the machine connect the ground. Please confirm whether the machine has connected

the ground, through the wire and the lead, to prevent the electric shock;

c. Use the proper fuse. Please use the stipulated type and rating fuse;

d. Provide good ventilation. This machine adopts the natural convective radiation. Fix it

correctly to keep it radiating well.

4. Please don’t disassemble and repair by yourself when it’s broken down. Please send to the

professional service department to solve the problems.

CAUTION：Please don’t assemble the machine in the moist environment;

Please don’t assemble the machine in the easy exploding environment;

Please don’t repair by yourself.

www.fmuser.org

www.fmuser.org

5

1. Overview

There are 4 types transmitter, 50W, 100W, 200W, 300W, in family TV transmitter. This kind

of TV transmitter is excellent, combining with TV modulation and power amplifier.

This TV transmitter is comprised of modulation cell and power amplifier cell; these two parts

have separate control and display system.

This TV transmitter provides a COM interface, which user can turn on or turn off TV

transmitter by remote command.

2. Technical Specifications

2.1. Technical Index

2.1.1 Video Index

1. Video input impedance 75Ω

2. Video input level 1.0Vp-p

3. Video modulating rate 87.5%

4. deferential gain ≤2.5%

5. deferential phase ≤2°

6. color/brightness delay 30ns

7. video response 0.75dB

8. video S/N ≥58dB（non coefficient added）

≥64dB（coefficient added）

2.1.2 Audio Index

1. audio input impedance 10KΩ（unbalance，lotus socket）

2. audio input level 0.775V

3. MAX audio freq deviation ≤±50KHz

4. Audio pre-emphasis 50us

5. audio frequency response ≤±0.5dB（40Hz ~ 15KHz）

6. audio distortion ≤1%

7. audio S/N ≥65dB

www.fmuser.org

www.fmuser.org

6

8. the distance between video and audio carrier 5.50MHz±500Hz

2.1.3 RF Index

1. RF frequency range

2. Frequency accuracy 5KHz

3. Total frequency deviation 20KHz

4 A/V ratio -8~-22dB(0.5dB step)

5 C/N ≥62dB

6. spurious output suppression ≤-60dB

7. RF output impedance 50Ω

2.1.4 Others

Power Voltage AC200V~ AC250V 47Hz~63Hz

Heat dissipation Forced ventilation

2.2 Physical Specifications:

RF output connector L16/L27

Casing Size 4U（484mm×172mm×600mm）、19Inch

Weight

Ambient temperature 5℃～+40℃

Relative Humidity ＜95%

Sea Level Height ＜4500m

3. System Structure and Function

This TV transmitter is comprised of two general parts, modulation cell and power amplifier

cell. Modulation cell contains power supply, modulation circuit, and control-display circuit; as the

same, power amplifier cell includes power supply, power amplifier circuit, and control-display

circuit (shown as figure 3-1).

Modulation cell put audio and video signal on the carrier RF signal. This control-display

www.fmuser.org

www.fmuser.org

7

circuit only work for the modulation cell, user can set parameter via this part.

Amplifier circuit contains preamp, power amplifier, and power monitor. The RF signal from

modulation goes to rated power after this amplifier circuit. This part also has separate

control-display circuit for listing the information as power, voltage, current, temperature, and

showing working status.

4. Test Instrument

Name Type Specification Manufacturer

Television Generator TSG-271 Tektronix

TV Monitoring Receiver PM5696 Philip

Video Measurement Set VM700A Tektronix

Audio Analyzer P1DD Audio Precision

Video Modulate

Audio Modulate

Preamp

Power

Amplifier

Power Supply

MCU

LCD

Display

COM

Interface

Figure 3-1 ZHC518A-50~300W TV transmitter

Structure and function

Power Monitor TV

RF Output

Key

Buttons

AC 220V

Input

Video Input

Audio Input Power Supply

LCD Display

Key Buttons

www.fmuser.org

www.fmuser.org

8

Wattmeter MODEL 43 0～1KW Bird

50Ω Attenuator DLA-1000W VSWR＜1.20

DC-1GHz BED

Table 4-1 Test instrument for ZHC518A-50/100/200/300W TV transmitter

5. Test and Maintenance

As a high performance and high index TV transmitter, ZHC518A-50/100/200/300W TV

transmitter’s relevant specifications such as distortion; audio frequency response, video frequency

response, and signal to noise ratio etc. totally meet the national relevant standards and industry

standards of TV transmitter, and some of their technical specifications is much higher than the

national standards and industry standards.

5.1 Performance Test

To ZHC515A family TV transmitter, video index and RF index need to be tested.

a. Connect transmitter and test Instrument with cable according Figure 5-1.

b. Adjust the output level of modulation; make the output peak power, which is read from

Wattmeter, to be rating power.

c. Test the video index according §2.1.

5.2 Maintenance

It needs to use new fans instead of the old ones which have worked more than 15000 hours. If

Figure 5-1 connecting for video index test

ZHC518A TV

transmitter Wattmeter Attenuator

RF RF

RF

Video

Video

TV signal

generator

Video

measurement

TV monitor

receiver

www.fmuser.org

www.fmuser.org

9

the digital FM broadcast transmitter works at a very dirty environment, for example a place with

much of dust, it must be to replace fans ahead of schedule.

6. Panel Description

6.1 Front Panel

6.2 Back Panel

www.fmuser.org

www.fmuser.org

10

7. Power on Sequence

7.1 Open the package, check appearance, switch, key button, socket, and interface port on front

and back panel.

7.2 Turn power switch on the “OFF” position and connect power cord to power source.

7.3 Connect audio, video, RF cable on the back panel. Connect RF out port to a 50 Ohm dummy

load or antenna through a cable.

7.4 Turn power switch to “ON” at the back panel, then turn power switch to “ON” at the front

panel.

7.5 Turn off RF power.

7.6 Set working parameters.

7.7 Turn on RF power.

8. System Control Logic

8.1 RF Output Control

This TV transmitter’s RF output can be controlled by RF Switch, which is on the “Main Page”

of the LCD.

When RF Switch is OFF, turn off RF power.

When RF Switch is ON, and the video signal input is normal, turn RF power on.

8.2 Remote Control

When remote control is enabled, remote LED on front panel is lit. And power output is

controlled by remote host and can not be changed locally except “Remote” flag is disabled.

RS232 or RS485 are used for remote control. User can ask either of this two. Before enabling

remote control, baud rate and device address should be properly set.

8.3 System Protection

In some urgent cases such as exceeded forward power, reflect power, current and over

temperature, system will reboot. If it is failed successive 3 times, the system will automatically

turns off RF power and just acts display function.

www.fmuser.org

www.fmuser.org

11

9. Direction for Operate and Display

To this TV transmitter, modulation cell and power amplifier cell have separate operate-display

system.

9.1 Operation for Modulation Cell

On the front panel, there is a LCD, “▲”Key, “▼”Key, “Select” Key, “Mode” Key for user to

view and set modulate parameter.

9.1.1 Video Modulating degree setting

Single click “Mode” key on the front panel, putting “LCD” Display under “paging” status,

and then ,pressing “▲” or “▼” key, making window frame at

If LCD displays picture 1, it means no video signal input.

If LCD displays picture 2 and video is AGC status, modulating degree automatically changes

to 87.5%.

When video frequency modulation is under MGC status, user can properly adjust the

potentiometer on the rear panel in order frequency modulation achieving perfect performance.

9.1.2 Audio Frequency Deviation Setting



Audio FREQ DEV： --------------------

Audio FREQ DEV： > > > > > >-------

图 1 图 2

Video MOD DEPTH： NO Signal&Input

Video MOD DEPTH： 87.5%

图 1 图 2

www.fmuser.org

www.fmuser.org

12

If LCD displays picture 1, it means no audio signal input, If LCD displays picture 2, user can

press “Select” key, entering variable status, and then, press “▲” or “▼” key, When deviation

appears at the middle, it means modulation frequency deviation ±50KHz. When deviation at the

full mark, it means ±100KHz.

9.1.3 A/V Ratio Setting



User can press “Select” key, entering variable status, and then, pressing “▲” or “▼” key

achieving desirable value, finally.(Suggestion: keep the factory default setting)

9.1.4 Program Label Setting



The factory default setting is 8 (A)s. If it is necessary to set program label, user can follow the

steps below:

Program： AAAAAAAA

A/V Proportion： - 18.0 dB

www.fmuser.org

www.fmuser.org

13

（1）When setting the first “A”, user can press “Select” key changing it to “*”, and then, pressing

“▲” or “▼” key, changing to desired letter.

（2）When setting the second “A”, user can press “Select” key changing it to “*”, and then,

pressing “▲” or “▼” key, changing to desired letter.

（3）Repeating step A or step B, until getting needed program label, finally pressing “Mode” to

save the change.

9.1.5 Output Frequency Setting



Frequency: 543.25MHz is the video carrier frequency.

Channel: 22ch means current channel is channel 22ch.

H means frequency changing step is 8MHz or 7 MHz, L means frequency changing step is

0.25MHz.

User can press “Select” key, entering variable status, and then, pressing “▲” or “▼” key

achieving desirable carrier frequency,.

9.1.6 Output Level Setting



Freque：543.25MHz

Channel：22ch H

Freque：543.25MHz

Channel：22ch L

www.fmuser.org

www.fmuser.org

14

“RF Level: Low” in picture means no output or output level is too low.

“RF Level: Norm” in Picture means output level is normal, “ATT: 0.0dB” means output

attenuation. User can press “Select” key, entering variable status, and then pressing “▲” or “▼”

key, until reaching user needed value, finally pressing “Mode” key saving the change.

9.2 Operation for Power Amplifier Cell

There is LCD, Up key, Down Key, Enter key on the front panel for user to operate and view

parameter of Amplifier Cell.

▲：Up key.

▼：Down key.

●：Enter key. User can select page and save parameter by this key.

When there is no operation (press button) for a long time, system will return to its main menu

automatically with LCD backlight off. Not saved updated parameter will be replaced with its old

value. Pressing any key can turn on the LCD again.

9.2.1 System Boot Up Page

Figure 9-1 Page of system boot up

RF Level：Low

ATT：0.0dB

RF Level：Norm

ATT：0.0dB

www.fmuser.org

www.fmuser.org

15

During the system boot up, company logo is displayed and all LED on front panel blinks 4

times (power LED is on). After system booting up, it enters to the page displaying frequency and

power set.

9.2.2 Main menu page

Figure 9-2 Main menu page

Figure 9-2 shows main menu page. This page contains the parameter as following:

RF SWITCH: RF switch control select between ON or OFF.

FWD POWER: forward power display only.

RFL POWER: reflected power display only.

AMP VOLTAGE: amplifier voltage display only.

DRV CURRENT: preamp current display only.

AMP CURRENT: power amplifier current display only.

[VIEW] parameter data browse menu, see [VIEW] menu.

[STATUS] system running status, see [STATUS] menu

[SET] parameter setting menu, see [STATUS] menu.

9.2.3 VIEW Page

www.fmuser.org

www.fmuser.org

16

Figure 9-3 Page of VIEW

Figure 9-3 shows the all parameters in the VIEW page. In the VIEW page, users can only

browse the parameters. If users want to modify the parameters, it should to be enter the SET page.

FWD POWER： forward power.

RFL POWER: reflected power.

AMP VOLTAGE: amplifier voltage.

DRV CURRENT: current of preamp.

AMP CURRENT: current of power amplifier.

TEMPERATURE: temperature of amplifier

BAUDRATE: baud rate used for serial communication.

ADDRESS: device address used for remote control.

REMOTE: remote control switch.

[EXIT] return to its parent menu.

9.2.4 STATUS Page

www.fmuser.org

www.fmuser.org

17

Figure 9-4 Page of STATUS

Two pictures in Figure 9-4 show the status of all parameters, users can find out the system is

running normally or not.

RF OUTPUT: ON/OFF; refer to control logic section.

ON: RF output is in normal status.

OFF: RF power is off.

SYSTEM: Normal/Error

Indicate system errors. Contact equipment provider when error happens.

FWD POWER: Normal/Warning/Protect

Normal: forward power is normal.

Warning: forward power is higher than setting power.

Protected: forward power is too high, RF power is turned off.

RFL POWER: Normal/Warning/Protect/Protect H

Normal: reflect power is normal.

Warning: reflect power is high, may cause RF power drop.

Protected: reflect power is too high, RF power is turned off.

AMP VOLTAGE: Normal/Warning/Protect

Normal: amplifier voltage is normal.

Warning: amplifier voltage is high, may cause RF power drop.

Protected: amplifier voltage is too high, RF power is turned off.

DRV CURRENT: Normal/Warning/Protect

Normal: preamp current is normal.

www.fmuser.org

www.fmuser.org

18

Warning: preamp current is high, may cause RF power drop.

Protected: preamp current is too high, RF power is turned off.

AMP CURRENT: Normal/Warning/Protect

Normal: amplifier current is normal.

Warning: amplifier current is high, may cause RF power drop.

Protected: amplifier current is too high, RF power is turned off.

TEMPERATURE: Normal/Warning/Protect

Normal: temperature is normal.

Warning: temperature is high, may cause RF power drop.

Protected: temperature is too high, RF power is turned off.


9.2.5 SET Page

Figure 9-5 Set Page

Baud Rate: select baud rate for remote control.

Address: set device address for remote control.

Remote: enable or disable remote control.


10. Indicator light

On the front panel, there are two lamps for modulation cell and eight for amplifier.

www.fmuser.org

www.fmuser.org

19

10.1 Lamp for Modulation Cell

10.1.1 Lamp for Power on

When this lamp is luminous, it means the power supply for modulation cell is normal.

10.1.2 Lamp for Video AGC

When video output is controlled by AGC, this lamp is light.

10.2 Lamp for Amplifier Cell

10.2.1 Lamp for Power on

When it is power on, the voltage of 5V is supplied normally, this green lamp is luminous.

10.2.2 Lamp for RF

When the RF SWITCH on the main menu is set to “ON”, this green lamp is light.

10.2.3 Lamp for Video

While output power is normal, this lamp is light.

10.2.4 Lamp for REMOTE

In the page of Set, if Remote is enabled, this yellow light is illuminant.

10.2.5 Lamp for TEMP

When the amplifier temperature is higher than 70℃, if temperature exceeds 85℃,it will

power off immediately.

10.2.6 Lamp for VSWR

If reflected power is higher than 2% of rated power, the lamp is light; higher than 4% of

power, it will decrease output power to decrease reflected power; when it is higher than 5%, it may

happen that: the software power off the output, or the hardware circuit switch off the power supply,

then power on again.

10.2.7 Lamp for GENERAL

If this lamp is light, it may happen that: forward power is more than 101% of rated power,

www.fmuser.org

www.fmuser.org

20

preamp current or amplifier current is higher than normal value.

if forward power is more than 110% of rated power, preamp current or amplifier current is too

much higher than normal value. it will shut down at once.

10.2.8 Lamp for RF MUTE

It means nothing for this mode of equipment.

11. Failure Check

11.1 Turn on the power supply, but the equipment doesn’t work

it may：

The fuse is broken: change the fuse;

The plug is not inserted tightly or contacted fault: insert the plug tightly.

11.2 No audio or video output

The source of audio or video signal is not connected: check the wire to ensure it has been

connected correctly.

11.3 Other Failure

If there is any other problem that can not be solved, please contact with Zhongchuan digital

equipment Co., Ltd.

zhc518a-50w~300w tv transmitter user's...

Documents