Transcript
AM 15000 SS Technical Description
Solid State AM Transmitters
TECHNICAL DESCRIPTION A.M. BROADCAST TRANSMITTER SENDER AM 15000 SS
June 2001
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AM 15000 SS Technical Description
Solid State AM Transmitters
TRANSMITTER CHARACTERISTICS 1. BASIC OFFER The basic offer includes: One AM15000SS A.M. Medium Wave Solid State Broadcast Transmitter. One Technical Manual.
2. SALES CONDITIONS 2.1 General Offered equipment corresponds to the latest state of the art technology and complies with international requirements and stipulated specifications. The equipment is fully tuned and tested at customer specified frequency, and is constructed and assembled using first quality components and materials.
2.2 Transmitter Components Three phase either 220V or 380V 50/60 Hz. Power supply with main A.C. isolation transformer and input R.F. filtering. One frequency synthesizer covering the 530 kHz. to 1700 kHz Band. One PWM modulator with two selectable power levels. 14 hot unpluggable power amplifiers. Control system for local or remote control of transmitter operation. Extensive front panel digital metering and signaling. Protective system including SWR, overcurrent, overvoltage, overtemperature, overpower, low drive, phase failure and other protections with sequential power reduction.
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Bandpass output R.F. filter with lightning protection. Low velocity air cooling system. Compact aluminum cabinet with locked front doors and stainless steel hardware, completely rustfree. One Technical Manual with specific test data.
2.3 Customer Required Relevant Information Mains A.C. supply is either 220 V +/- 10%, 47 to 65 Hz or 380 V +/- 10%, 47 to 65 Hz, as required by the customer. Other voltages and frequencies may be available upon request. Power supply includes main circuit breaker and Varistor transient protection. Output connector is 50 ohms 1-5/8" E.I.A. flange. Dimensions and weight: -
Width: 31-1/2 in (80 cm)
-
Height: 71-1/4 in (181 cm)
-
Depth: 31-3/4 in (81 cm)
-
Gross Weight: 1102 lb (500 kg)
2.4 Warranty Equipment shall be in warranty for a period of 24 months from the delivery date. The transmitter shall be guaranteed against all defects that should arise as a cause of defective material and or workmanship, unless such defects can be proved to be due to misuse, mishandling or installation conditions not complying with the requirements included in the transmitter Technical Manual. Under warranty conditions, SENDER will replace or repair any defective part, free of charge.
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AM 15000 SS Technical Description
Solid State AM Transmitters
The warranty is conditioned to a correct transmitter installation specially regarding grounding, lightning protection, A.C. supply transient protection and A.C. supply voltage limits.
2.5 Spare Parts SENDER ensures the availability of spare parts and components for a period of 10 years from the delivery date. In the event that an exact spare may not be available, a suitable replacement shall be supplied . Sender undertakes to perform any necessary modification required to accept a spare part different from the original, for a period of ten years. A basic set of spare parts including fuses and semiconductors is optionally available upon request.
2.6 Delivery Confirm with the factory. Usually 30 days from the date of contract signature and deposit, the offered equipment will be ready for acceptance test, unless other agreement. If the client decides not to participate in the factory acceptance test, official written notice must be given and the delivery will follow immediately afterwards.
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Solid State AM Transmitters
3. PRODUCT DESCRIPTION SENDER AM 15000 SS broadcast transmitter is designed to operate in any channel in the frequency band between 530 kHz and 1700 kHz. The nominal R.F. carrier power is 11 kW with 150% modulation capacity into a 50 ohm load. When operating at carrier level of 12 kW modulation capacity is 125%. Maximum carrier power is 13 kW with 100 % modulation capacity. All SENDER Transmitters are fully Solid State, using a modular redundant architecture, employing class D high efficiency R.F. power amplifiers and polyphase PWM modulators. The transmitter includes a frequency synthesizer that may be easily adjusted to operate in any channel inside the A.M. band. The equipment uses a 220V (380V option available) 47 to 65 Hz three phase power supply. The transmitter is supplied with two independently adjustable power levels. Power levels may be locally or remotely selected and may be preset between 0.1 and 1.2 times the nominal power. In addition, a step type power control permits a +/- 15% fine adjustment of the preset power level. This adjustment may be commanded locally or by remote control. An external interface permits monitoring the most important operating parameters and to command main functions.
3.1 Physical Description The transmitter is contained in a double compact cabinet. construction employed uses nine different assemblies: A1
The modular
Power Supply.
A1A1 Regulators/ filter capacitors sub-assembly. A1A2 Capacitor discharge and 270 V addition subassembly A2
Control.
A2A1 Commands, measurement and alarms subassembly
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A2A2 Alarm multiplexer A3
PWM modulator (PWM=Pulse width modulation).
A4
Synthesizer.
A5
Modulated Power Amplifier
A5A1 Amplifier Nº1 A5A2 Amplifier Nº2 ----------------A5A14 Amplifier Nº14 A6
PWM distributor
A7
Back Panel
A7A1 Motherboard A7A2 R.F drive amplifier and tuning. A7A3 R.F. summing transformer A8 Output filter. A8A1 Directional wattmeter sub-assembly. A8A2 Transient suppressor sub-assembly. A8A3 R.F. samples subassembly. A9 Blowers. Audio and remote control connections are located in a terminal board in the transmitter back. The mains connection is included in a terminal board located at the transmitter base plate. The 1-5/8" E.I.A. R.F. output connector is located in the right back side of the transmitter top. A BNC connector located in the back of the transmitter provides a sample suitable to operate a modulation monitor. June 2001
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AM 15000 SS Technical Description
Solid State AM Transmitters
The fresh air inputs through the lower part of the cabinet back, through a metallic washable filter and exhausts through the top.
3.2 Functional Description Transmitter functional blocks are:
1) A1 Power Supply. Located in the lower compartment of the transmitter, with the following functions: A.C. mains connections and transformer tap selection. Ferrite toroids in the A.C., audio and external interface conductors, to limit the effects of an eventual strike in the A.C. distribution lines or in telephone lines. Circuit breaker with overload and short circuit protection of the A.C. feed. Rectification and filtering of the main D.C. voltage. Rectification, filtering and regulation of the auxiliary D.C. voltages. Inrush current limiting. Discharge of the filtering capacitors. Current and voltage samples generation, to be used by the control system. Varistor transient protection.
2) A2 Control. The control card includes the following signaling and command elements:
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Solid State AM Transmitters
DENOMINATION
FUNCTION
INDICATION
A2S1 (OFF)
Off
LED (Green)
A2S2 (ON)
On
LED (Red)
A2S3 (Reset)
Alarm reset
--
A2S4 ( · )
Upper and lower amplifier measurement 2 LED (Yellow) selection.(Bmod, IPB, tºR.F., tºPWM).
A2S5 (
)
Advance multimeter reading.
--
A2S6 (
)
Reverse multimeter reading.
--
A2S7 ( -- )
Selects power meter reading.
--
A2S8 ( P1 )
Selects power level 1.
LED (Yellow)
A2S9 ( P2 )
Selects power level 2.
LED (Yellow)
A2S10 (
)
Output power increase.
A2S11 (
)
Output power reduction.
A2S12 (LcRm) ·
Selects between operation.
local
and
remote 2 LED (Yellow)
The control board includes two digital meters. Following parameters can be measured: +B voltage in each P.A. Modulator current in each P.A. R.F. amplifier temperature in each P.A. PWM amplifier temperature in each P.A. Main supply D.C. voltage. Main supply total current. R.F. drive R.M.S. voltage. R.F. drive current. Synthesizer PLL control voltage. June 2001
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AM 15000 SS Technical Description
Solid State AM Transmitters
+9V auxiliary supply voltage. -15V auxiliary supply voltage. Incident power. Reverse power. The control board contains the necessary circuits to display the operational parameters scaled accordingly. Protective circuits and connectors used to distribute signals and D.C. voltages to other boards are also included. A connector is provided to install a battery to freeze the alarm status in the event of a power failure.
3) A3 PWM Modulator. The PWM modulator uses an instrumentation type audio amplifier with balanced input. Two PWM pilot signals with a relative phase displacement of 180º are generated from a crystal controlled frequency reference. This dual phase technique improves the output spectrum, reducing the components associated with the fundamental of the pilot frequency. The modulator includes electronic circuits with the following functions: Soft start. Automatic power control. Discrete and quasi-continuous power adjustment. Balanced to unbalanced audio conversion. Adjustable positive and negative peak limiter. Hum and noise compensation. Fast protection through PWM signal disable.
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4) A4 Synthesizer. The synthesizer generates a high stability R.F. drive signal at carrier frequency. Frequency is defined by the position of a set of dip switches. A BNC socket accepts an external reference signal for C-QUAM. stereo operation.
5) A5 Modulated Power Amplifier. The modulated power amplifier includes 14 identical modulated amplifiers that are easily plugged or unplugged into a motherboard. Each modulated power amplifier is included in a single PCB. The R.F. power amplifier is of the bridge type and operates in class D. The PWM power stage includes two hexfets, of the same type used for R.F. amplification, each one associated with its own filter and damper diode. The amplifiers can be hot plugged or unplugged, in a motherboard that includes contacts for the main D.C. voltage, R.F. drive and R.F. output. A DB-25 socket in the front of each amplifier accepts the PWM pilot signals, auxiliary D.C. voltages and command, signaling and measurements signals. Each amplifier is internally protected against low drive voltage, overtemperature, drive unbalance and output short circuit. For safety reasons, a spring loaded switch discharges the amplifier filter capacitors when the PCB is unplugged.
6) A6 PWM Distributor. The PWM distributor subassembly receives the 0º and 180º PWM pilot signals and distribute them to the 14 power amplifiers.
7) A7 Back Assembly. The central section of the transmitter back includes a box containing the sockets where the power amplifiers are inserted, and the R.F. drive amplifier and tuning circuits.
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A7A1 Motherboards. Includes the 31 pin sockets that receive the power amplifier plugs. Mentioned jacks feed the drive signal, RF output signal, D.C supply and the insertion loop. To avoid the generation of dangerous voltages when one amplifier is removed, a switch that operate when its associated power amplifier is removed, shorts the primary winding of the output transformer corresponding to the removed amplifier. Mentioned switches are actuated trough the guide pins of the power amplifiers. A7A2 R.F. Drive amplifier. The R.F. drive amplifier is included in one PCB and contain electronic circuits that performs the following functions: -
Series tuning of the drive amplifier input
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Drive signal power amplification.
-
Series tuning of the drive signal.
-
R.F. drive voltage and current measurement.
A7A3 R.F. Summing Transformer. The output transformers for the power amplifiers are located close to the back plane PCB. Mentioned transformers have an isolated secondary winding that is series connected to add the power of the 14 amplifiers.
8) A8 Output Filter. Following functions are assigned to the output filter: To adapt the load impedance to the value required by the amplifiers. To attenuate the harmonics present at the amplifier's output. To protect against antenna over-voltages and transients. The output filter is assembled using frequency dependent coils and capacitors and is located at the transmitter top section. A8A1 Directional Wattmeter. The directional wattmeter generates voltages proportional to the square root of the incident and reverse power. Mentioned voltages are processed in the control board, used to protect the transmitter against excessive VSWR conditions and to June 2001
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AM 15000 SS Technical Description
Solid State AM Transmitters
display the direct and reverse power. Additionally, the wattmeter board includes a BNC socket with an R.F. sample adequate for the operation of a modulation monitor. A8A2 is a subassembly includes a solid state transient protector. A8A3 is a subassembly that includes R.F. output current measuring transformer and R.F voltage sampling capacitors. A8A4 is a subassembly including the R.F output connector and the spark gap. A8A5 is a subassembly similar to the directional wattmeter but sampling the impedance magnitude at the input of the output filter.
9) A9 Blowers. The power amplifiers are cooled forcing air through the extruded heatsinks. Two sets of blowers are located in the transmitter central compartment, one set below and one above the power amplifiers.
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AM 15000 SS Technical Description
Solid State AM Transmitters
4. SPECIFICATIONS 1. Frequency range:
530 kHz to 1700 kHz.
2. Output power :
11 kW with 150% modulation capacity. 12 kW with 125% modulation capacity. 13 kW with 100% modulation capacity.
3. Maximum power to operate with 100% modulation, continuous tone: 12 kW. 4. Power reduction:
Two levels standard, up to four upon request, +/- 15% fine adjustment.
5. Configuration:
Modular redundant, with 14 hot unplug-gable and interchangeable power amplifiers.
6. A.C. power source:
220V (or 380V), 47 Hz to 65 Hz, three phase. Other voltages or frequencies upon request.
7. R.F. Output impedance:
50 ohms unbalanced.
8. Max S.W.R.:
1.5:1
9. Output connector:
Type 1-5/8" E.I.A. Flange.
10. Harmonic and spurious radiation:
Lower than -80 dB referred to carrier, at nominal power.
11. Frequency stability:
Better than +/- 5 Hz from 32ºF to 122ºF (0ºC to 50º).
12. Audio response:
Better than +/- 1 dB between 30 Hz and 10 kHz.
13. A.F. distortion:
Less than 1% @ 90% modulation, 30Hz to 10 kHz, at nominal power.
14. Noise and hum :
Less than -63 dB measured in a 20 Hz to 22 kHz band.
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Solid State AM Transmitters
15. Carrier shift:
Less than 1% between modulation at 400 Hz.
0%
and
95%
16. Audio input level:
+10 dBm nominal. Internally adjustable between 0 dBm and +13 dBm.
17. Efficiency:
> 80%
18. Temperature range:
Storage: Operation:
20. Altitude:
0 to 10000 ft (3000 meters) above sea level. For higher altitudes consult factory.
21. Humidity:
0 to 95% non condensing.
22. Size and weight:
Width: 31-1/2 in (80 cm) Height: 71-1/4 in (181 cm) Depth: 31-3/4 in (81 cm) Gross Weight: 1102 lb (500 kg)
5ºF to 167ºF (-15ºC to +75ºC). 14ºF to 122ºF (-10ºC to +50ºC).
NOTE: Specifications may change without notice.
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