Communication has always been an important tool in the society. It bridges one people with another and helps to reduce the gap between them. Nevertheless, when there is a stretch of distance between the two, then what should you do? Well, you communicate by means of technology called telecommunication. Here, information, message, signals, images, writings or any kind of thing that is worth sharing, is shared via telephone, radio, cable or other electro-magnetic options.

Phase Lock Oscillator and Satcom Modem facilitate telecommunication via Satellite allowing long distance access where there are no Fibre Optic connections. This is particularly useful for third world country access and Ocean going Ship traffic.

Phase Lock Oscillator

The striking features of a good PLO or Phase Lock Oscillator is its frequency stability in the order of 0.1ppm (parts per million) This allows multiple channels to co-exist in close proximity to each other without affecting each other. Raditek offers these with great pricing and low phase noise. These oscillators can again be classified further into Dielectric Resonant, Coaxial Resonant and Ceramic Resonant. Raditek offers these with a frequency range of 300MHz to 42 GHz. These can be harmonically locked to both external and internal references.

Choosing which PLO should be implemented depends on the requirement of the situation. And the parameters that should be considered while choosing a good PLO are- spectral quality (harmonics, spurious, phase noise etc.), output frequency, reference frequency (both internal and external) etc.

As mentioned earlier, Phase Lock Oscillators have varied sources, which hint at their capabilities. So, if you need this type of oscillator, then contact Raditek to talk with the designers to understand the best solution for your project. Our experts will know the exact components you require and will prescribe the best solution paying attention to both performance and pricing.

Satcom Modem

This Satcom Modem is another element of a Satcom telecom system, used in various bands like S, L, X, C, Ka and Ku etc. Model choices include the Dream and Extreme. The Dream includes ABOD (Adoptive Bandwidth on Demand) and DAMA (Demand Assigned Multiple Access).

The Extreme is an advanced modem that acts as demodulators and modulators (which the basic work of a modem). The features vary depending on their use. There are many more details and deviations available for satcom i.e. satellite communication,depending on further needs. There are ups and downs convertors as well.

All these variations prove how important both these technologies are. If you really need to get hold of one, then consult the Raditek experts in telecommunications.

SSPAs – Solid State Power Amplifiers basic design finds extensive use in telecommunications, radar applications, defense applications in missile warfare and airborne communications. RF (Radio Frequency), SSPAs,are manufactured with cutting edge technology as diverse applications are made possible. These power amplifiers provide high performance is adverse conditions. High Power microwave SSPAs are based on Power summation concept and are the best alternative to TWT – traveling wave tube technology-based amplifiers. Amplifier designs with Gallium Arsenide or Gallium Nitride power devices are most common.

Generally, SSPAs Solid State Power Amplifiers are designed to customer requirements. The applications differ from customer to customer particularly in the defense sector such as Airborne radars. Generic SSPAs find use in communication and transmission applications in X and Ku Bands as the flexibility of the microwave SSPA design allow the ability to extend to neighboring frequency bands. SSPAs in space applications are growing considering the number of satellite launches. InJanuary of 2017 SpaceX Falcon 9 rocket launched 72 low Earth and mid-Earth orbit satellites.

Among the leading SSPA product line is Raditek. Their catalog has an impressive listing that suits every application. Among their other products is the low noise block downconverter which is the device in the center of a satellite dish. The LNB (abbreviation) receives low-level signals from the satellite. The LNB amplifies the signal and changes to a lower frequency. The receiver (inside the building) demodulates the signal that is traveling from the LNB via a coaxial cable. The block is a set of microwave frequencies received from the satellite and down-converted to lower frequencies. LNBs are weatherproofed to withstand exposure to the elements.

Electromagnetic waves tend to become weak with distance. Signal frequency requires repeatition to reach long distances the use of phased lock loops in matching the frequencies form an important part of integrated circuits.

Typical communication systems constitute particular communication networks and transmission technologies. Data terminal equipments are the bridges that interconnect and allow the system to operate as a whole. The integration works, provided the procedures and controls are technically compatible meaning they speak and understand each other. Telecommunication is one such communication system, so too are data networks which carry voice, video and data streams.

Prediction by Gordon Moore

Digital technologies are accelerating at a pace never witnessed before. Integrated circuits which constitute the major component in an electronic circuit are becoming denser. One of the main building blocks in electronic circuit technology are PLL short for phased locked loops. PLL came into existence around the 1930s. Gordon Moore, one of the founders of Intel made a bold prediction in 1965 that the number of transistors in a single IC (integrated circuit) would double every two years. (His initial prediction stated that the doubling would happen every year). The prediction has stood firm for over fifty years even though IC technology has become more complex.

The exponential growth of technology has led to the rise of PLLs in ICs. Basic PLL consists of a phase detector, low pass filter, and aVCO – Voltagecontrolled oscillator. The following applications among others have extensive use of PLLs

•  Frequency modulation as in FM networks and stereo decoders

•  Frequency synthesis

•  Motor controllers

Filtering noise from low-frequency applications was the earliest use of PLLs. Improvements in IC technology has led to thefeasibility of PLLs in high-frequency areas. In television transmission, PLLs are an important component in variable frequency filtering and regeneration of chopped signals.

PLLS and Bucs in Satellite Communication

Satellite signal transmission use PLL oscillators in the block upconverters (Buc).They convert lower frequency bands to ahigher frequency. Present day Bucs convert the L-band frequency signals to Ku band and C band frequencies. The L band refers to the electromagnetic spectrum of 1 to 2 GHz for communications.Working in tandem with a 10 MHz reference frequency the Bucscan transmit at the correct frequency. Bucsare used along with LNBs (The small device in front of dish antennae). LNBs are low noise block converters are on the receiving side of the transmission while the Bucs are on the transmitting side. VSAT systems utilize the Buc and LNB for bidirectional internet access from satellites. The Buc converts low digital frequencies into high radio frequencies allowing the wave to travel into space. Satellites and space crafts in earth orbits can access these high-frequency RF waves. Several frequencies form bands that carry data sets. Each transmission has unique identifiers allowing for aspecific instruction to and fro from the satellites to ground-based controllers.

Upconverting is the process of converting the intermediate frequencies to a block of higher frequency signals. The upconverter, for example, uses a Local Oscillators and can be found in Radio telecommunications systems and computers. For highest frequency stability, and best phase noise, a phase locked local oscillators is typically used. A DRO (Dielectric Resonant Oscillator) can be used for a fixed frequency Local oscillator.

Phase Locked Loop (PLL)

A PLL is an electronic circuit that consists of a voltage controlled oscillator (VCO)with a phase detector a reference oscillator (usually a crystal oscillator) and an active loop amplifier/designed loop bandwidth.A phase locked loop is a control system that generates an output signal with a phase related to that of the higher stability reference signal

How Does A PLL Work?

A PLL has the few major components to perform the following functions:

– The VCO (voltage controlled oscillator) that generates an RF signal – The phase detector that compares the phase of the reference signal with the generated signal – The phase detector continually adjusts the oscillator to match the phase and frequency

Uses of a PLL

– To demodulate a modulated RF signal – To recover a signal from a high noise environment. – To generate a stable frequency at multiples of a reference frequency – To generate precisely timed clock pulses in digital logic circuits

Block Upconverter (BUC)

Transmission of satellite signals usually takes place with the help of Block Upconverter (BUC). It converts a band of frequencies from a lower IF (intermediate frequency) to higher frequency. Modern BUCs convert from L band to C, KU band and Kaband, for example.

Low Noise Block Downconverter LNBs (receive) and BUCs (Transmit) typically use phase locked loop local oscillators which usually require a (10 or 100MHzetc) frequency reference to maintain a stable transmit and receive frequency.

In the world of satellite communication, a lot depends on the proper transmission and reception of signal. LNBs are critical to amplify the received satellite signal with minimal noise contribution.

Low-Noise Block down Converter

A low-noise block down converter comprises of a receive-only amplifier and down converter mounted on the satellite dish. There are many individual components in a low-noise block down converter,including a low-noise amplifier, frequency mixer, local oscillator and intermediate frequency amplifier. The low noise block converter gets the power from the receiver or set-top box via the coaxial cable that carries the signals from the LNB to the receiver.

The Working of an LNB

The low-noise block down converter works in the following way:

– The dish receives the satellite signal – The LNB amplifies the signal – The signal is then down converted to a lower block of intermediate frequencies. In this process, the signal is sent by a low cost coaxial cableto the indoor set top box/DVR or satellite modem.

Why are LNBs Required?

LNBs are mainly used to down convert a block of frequencies to intermediate lower frequencies.

The satellites use high frequency microwave frequencies. The microwave signals are not able to easily pass through walls, roofs or even glass windows. The satellite receive-only dish and LNB are mounted outdoors and the residential set top box or modem, indoors.

Low-Noise Block down Converter Placement

Since the first signal frequency conversion takes place at the satellite dish, the LNB is usually mounted on a short feed arm at the focal point of the reflector (of the dish), or for larger dishes, with a different (egCasegraine) feed, behind the reflector. It is a relatively small unit and is easy to mount onto the waveguide feed of the dish. This placement allows the LNB to receive the microwave signal via the feed and waveguide interface flange.

The microwave signals received by satellite dish use the low-noise block down converter to convert the received (from satellite) signal to a lower IF frequency for simple low cost connection via coaxial cable to the residential set top box or receiver/DVR or satellite modem thus simplifying (at lowest cost) the entire communication system.

Radio frequency (RF) includes any of the electromagnetic wave frequencies from around 3 kHz to 300 GHz, which include frequenciesused for communications or radar signals. Extremely to very low frequency (to 20KHz) are generally sound based and can be heard by most humans.

These are the radio spectrums after which are the light spectrum and then the radiation spectrum which includes x-rays, gamma-rays and cosmic rays.

The Radio Spectrum

Sound (audible) is in the VLF range of upto 10/20KHz KHz (Kilohertz) while ultra-sonics range from 10 KHz to 1 MHz (Megahertz). Radio broadcasts are either AM (LF to MF) or FM (HF to VHF). Microwaves are in the VHF to EHF range and may extend further as the understanding and measurement becomes more advanced.

Frequency spectrum is licensed by the respective Governments in the interests of security and delivers a level playing field for telecom enterprises. In between FM broadcast and UWB lie the ISM bands. The lower range of ISM bands belong to the 315 – 915 MHz while at present ISM bands are also allowed in the 2.4 GHz range. ISM pertains to Industrial, Scientific and Medical uses which include Space, defence, electronic disruption, radar and navigation systems.

Raditek is a leading manufacturer of amplifiers in ISM band and their products are increasingly used in medical laboratories, EMC (Electromagnetic compatibility) and plasma physics.

Noise is always present in communications. Electronic systems generate some form of unwanted energy as spurious in the radio frequency. This unwanted energy termed as spurious signals (which can be harmonically related to the wanted signal, or not) and seen as spikes in a spectrum analyser can cause performance degradation withall data streams,including digital signal processing of video signals, for example. To overcome this noise, a product known as phase lock oscillator (PLO) is used, as the local oscillator in the BUC (Block upconverter). If the PLL (phased lock loop) is missing then television receivers will receive distorted, noisy images.

Types of PLO

Raditek is a San Jose based RF and wireless telecom manufacturer of systems, components and modules. They provide PLO (phase lock oscillator) from

Simple crystal oscillators (referred as XO) that is nearly 1000 ppm (parts per million) accurate followed by TCXO (temperature compensated crystal oscillator) with accuracies between 1 to 10 ppm.

The oven compensated crystal oscillator (OCXO) is accurate between 0.1 to 1 .0 ppm while expensive Caesium based (in atomic clocks) and Rubidium based oscillators are used as a reference with the highest stability.

Broadband connectivity is pervading almost every aspect of day-to-day living and with IoT (internet of things) increased visibility to high end performance in the C, Ku and Kasatcombands has become common place. The importance of Block upconverter (BUC) is critical , typically located close to the transmit antenna (which can be mobile as well as fixed).Satcom modems typically feed anL-band signalto an outdoor BUC after amplification and upconversion to the output frequency.  BUCs comprise of:

• SSPA – solid state power amplifiers

• Upconverter with a mixer, phase locked local oscillator and bandbass filters • IF (intermediate frequency) amplifier

• Power supply from a DC source.

Typical BUCs range in power levels depending on the frequency such as

• Ka band can deliver power from 1 to 15 watts to 100-200Watts

• X and Ku band can deliver power between 2 to over 1200 watts

• While C band can deliver power from 2 to 2000 watts.

Being passive, filters and diplexer’s main challenges are improved performance over ever more difficult environmental specs and tighter frequency plans; needed better roll offs, for improving spectral efficiency.

What are BP Filters and Diplexers?

The band pass filters and diplexers encompass a variety of specifications. This leaves the designers to minimize the level of mutual interactions and create parallel connections with the help of optimization routines. Such 3-port diplexersmay additionally require the combination of three or more different frequency bands through one common diplexer or filter. This is used for multiband applications, covering multiple satellite bands, for example.

The BPF allows the mid pass band to travel through it, whereas the band reject filter allowsonly the upper as well as lower bands to travel. Many configurations are possible, maximally flat, steep roll offs requiring increased number of filter poles for example, and higher rejection bands etc.

The Design Strategy

Since optimization routine occupies a crucial role in reducing the level of mutual interaction between final response shaping and filters, here are some of the necessary steps that define its overall strategy –

• Quickly estimates the transfer functions of both the filters • Create net list of filters and diplexers • Carrying out optimization for refining the final responses • Translating the list into preferred technologies for the realization of diplexer

Phase Lock Oscillator – Another Advanced Innovation

A phase lock oscillator is available in diverse frequency range varying exceeding 1 GHz to 42 GHz. It is unmistakably a premium component for higher frequencies in harsh environments.

Improving the overall phase noise performance, while pushing the upper frequency is always a challenge. Additional constraints of vibration resistance, radiation hardened semiconductors and shock, while maintaining the required phase noise is the ultimate challenge for these.

Highly power RF requirements are growing as new areas of usage in a diversity of applications ranging from microwave ovens to particle accelerators and from self-cauterizing scalpels for surgery to very high power TWTA replacement amplifiers for satellite and terrestrial communications. With VED (Vacuum Electronic Devices) historically being the highest level of RF and microwave power, Considering the continuous advancements in technology, one can also find hybrid forms of solid state combined with TWTA (Travelling Wave Tube Amplifiers) in various combinations of standalone and redundant configurations.

The Leading SSPA Suppliers

While considering the suppliers, you need to check the background and history of Raditek, as the leading supplier of Solid state (SSPAs)and TWTA based power amplifiers or BUCs (Block up converters). The bandwidth that a solid state amplifier support keeps getting wider and higher in frequency as the applications grow and operating frequencies keeps advancing. Here is a brief description about the applications of these SSPAs (Solid State Power Amplifier) that can help you gain its better understanding

Space Qualified Applications

Space qualified applications, such as for satellites are growing as the LEO (low earth orbit), MEO (mid Earth orbit) as well as the Geo-stationary satellites grow hugely in number. Microwave amplifiers ranging from L band to 40GHz lead the GaN technology for the SSPA power levels, plus the need for high reliability, radiation hardened forms of he semiconductors, to prevent early failures in the presence of certain radiation levels encountered in space. Power and frequency increases are ongoing. And it is improving/advancing at a fast pace, as new, ever smaller geometry devices keep being developed.The linearity plays a pivotal role for the amplifiers when it comes to communication systems. TWTAs now include linearizers, which makes them perform similar to their SSPA counter parts. SSPAs at very high powers requires the combining of many smaller power amps and pre amps, which take a lot more room and offer special challenges for all outdoor and especially space applications, where size and weight are a premium. The TWTAs are much more compact and efficient at the higher powers, as well as offering much more straight forward architectures for redundancy.

The biggest challenges for the space qualified SSPAs include flexibility in size and physical construction. Although the space industry emerges as inherent conservative in terms of approach, it always tends to often conservatively stick with the well-proven technology instead of risking the processes on latest developments, until fully proven out over time and experience.

Medical and Industrial Applications

Being narrow in bandwidth, these medical applications particularly target the higher power levels up to more than 10 KWs. The SSPAs find their greater preferences in this market due to their instant availability, robustness. Following an upgradable path in power and frequency, the companies use this renewable/upgradable technology to protect their equipment investment for long term.

Broadcast and Communications

With the growing costs and competition of spectrum in this industry, you can experience a great shift towards microwave amplifiers to increase the bandwidth of modulations. With the insatiable demands of high data rates, the industry is looking up for such systems that are efficient in terms of power back-up levels.

Being the most crucial and expensive component of any microwave system, the SSPA solid state power amplifier is gaining huge acceptance in the field of communications, radars, missiles and airborne and space applications.

1. RF/microwave power Amplifiers are used in wireless communications, and also in applications such as jamming, imaging and RF heating.

2. Each application has its own unique requirements for power, frequency, bandwidth, load, efficiency, linearity, and cost.

4. An SSPA (Solid State Power Amplifier amplifies the input power into a larger of RF/microwave output power. There are a great variety of different PAs, and most employ techniques beyond simple linear amplification,

5. A transmitter contains one or more PAs, as well as ancillary circuits such as signal generators, frequency converters, modulators, signal processors, linearizers, and power supplies. The classic architecture employs progressively larger PAs to boost a low-level signal to the desired output power.

6. However, a wide variety of different architectures in essence disassemble and then reassemble the signal to permit amplification with higher efficiency and linearity

7. Almost every conceivable type of modulation is being used in one system or another. PAs and transmitters also find use in systems such as radar, RF heating, plasma generation, laser drivers, magnetic-resonance imaging, and miniature dc/dc converters.