Direct digital synthesizer enables superior recovered timing signal

27 March 2002 Telecoms, Datacoms, Wireless, IoT

In optical communications systems, there is frequently a need for recovering a timing signal from a data stream. The recovered timing signal often displays unacceptable jitter and noise characteristics. It is desirable to clean up a 'dirty' timing signal to obtain one that is jitter- and noise-free.

A common solution for cleaning up a jittery timing signal is a PLL (phase lock loop) with a suitably designed analog loop filter. This analog loop filter design must be optimised for a relatively narrow set of operating conditions. Also, this filter may be highly dependent upon the accuracy of several component values in order to achieve acceptable performance. This can make such a filter expensive and the resulting solution inflexible.

Analog Devices says that much better results can be obtained through the application of its AD9852 DDS (Direct Digital Synthesizer) in a digitally controlled oscillator (DCO) configuration. This design uses a digital processor (such as a microprocessor or DSP) to implement the PLL loop filter in software. This digital loop filter can be complex to achieve any desired transfer function, and can also be adaptable or reconfigurable for changing circumstances.

The DCO shown in the diagram takes advantage of the ultra-fine tuning resolution of the AD9852 DDS. This 300 MSa/s DDS features a 48-bit frequency tuning word that achieves 1 milli-Hz or better resolution in frequency settability. The AD9852 also features a parallel interface port that allows the controller to update its tuning value very quickly.

The combination of microhertz digital tunability and the digitally implemented PLL loop filter leads to a superior recovered timing signal and unmatched flexibility of design, according to the company.

Further reading:

Smart farming with LoRaWAN
Otto Wireless Solutions Telecoms, Datacoms, Wireless, IoT
Real-time visibility is transforming modern agriculture, and Otto Wireless Solutions, together with Dragino, deliver this capability through a comprehensive suite of long-range IoT sensors and gateways designed for smart farming.

Read more...

---

RTK-enhanced GNSS and INS solution
Dizzy Enterprises Telecoms, Datacoms, Wireless, IoT
This latest XSENS MTi-8 Click provides high-accuracy positioning (RTK-supported) and orientation tracking in demanding outdoor embedded applications.

Read more...

---

High-performance double balanced RF mixer
RFiber Solutions Telecoms, Datacoms, Wireless, IoT
The AM5008 from Mercury Systems is a high-performance, double-balanced MMIC mixer designed for wideband applications spanning 2 GHz to 24 GHz.

Read more...

---

Compact NFC antennas enable easy integration
Telecoms, Datacoms, Wireless, IoT
Leankon has expanded its 13,56 MHz NFC antenna portfolio with a comprehensive suite of nine off the shelf products designed for next generation IoT applications.

Read more...

---

Ultra-low jitter clocks
Altron Arrow Telecoms, Datacoms, Wireless, IoT
Skyworks has introduced a new family of ultra-low jitter programmable clocks designed to meet the increasing demands of next-gen connectivity.

Read more...

---

Efficient Bluetooth SoC
Altron Arrow Telecoms, Datacoms, Wireless, IoT
The EFR32BG29 wireless SoC from Silicon Labs is a highly efficient, high memory, low-power, and ultra compact SoC designed for secure and high-performance wireless networking for IoT devices.

Read more...

---

Minimal size, maximum flexibility
Würth Elektronik eiSos Telecoms, Datacoms, Wireless, IoT
Würth Elektronik has introduced two highly compact radio modules that give developers maximum freedom in designing proprietary wireless solutions that go beyond standard protocols.

Read more...

---

Super Wi-Fi extends industrial connectivity
NEC XON Telecoms, Datacoms, Wireless, IoT
Africa’s harshest mines, ports, and industrial parks are no longer bound by range, latency, and interference challenges.

Read more...

---

HackRF Pro advances Open SDR performance
IOT Electronics Telecoms, Datacoms, Wireless, IoT
Designed for engineers, researchers, and radio enthusiasts alike, the HackRF Pro can transmit and receive signals across a wide frequency range of 100 kHz to 6 GHz, making it a versatile tool for testing and developing modern and emerging radio technologies.

Read more...

---

Deterministic high-speed Ethernet
Telecoms, Datacoms, Wireless, IoT
The Fraunhofer Institute for Photonic Microsystems IPMS has developed a new 10G TSN endpoint IP Core, enabling deterministic real-time communication at data rates of up to 10 Gbit/s.

Read more...

---