Example Consulting Projects
Extensive experience with technology development and technical management of communications-related systems and products for commercial, consumer, and government applications. Experience base includes cellular telephones, cable modems, OFDM-based wireless networking at 5 GHz, ultra-wideband systems, detailed RF systems engineering, satellite telemetry systems, and a wide range of digital signal processing disciplines. Equally comfortable performing as an individual contributor, traditional full-time employee, or entrepreneur.
Senior Fellow, Sequoia Communications 2006 – 2008
Individual contributor to Sequoia’s advanced polar transmitter for 3GPP GSM / EDGE / WCDMA transceiver. Sole inventor for two of the key signal processing algorithms needed for its success. Provided design guidance for RFIC designers concerning all frequency sources in multiple chip designs. Member of the executive staff.
Co-Founder, President Silicon RF Systems, Inc. 2003 – 2006
Development of advanced RFICs in SiGe, bipolar & CMOS technologies for consumer & commercial applications.
Co-Founder, Former VP of Engineering, and CTO Magis Networks, Inc. 1999-2003
As founder and the original VP of Engineering, hired many of the core engineering team including director-level staff as well as his own replacement. Was the primary architect for the complete baseband digital signal processing physical layer solution and also architected the 5 GHz radio transceiver in detail. Played an active role in the RFIC and BBIC developments, antenna development and extensive field-testing. Pioneered improving wireless channel reliability in order to deliver Quality of Service (QoS) for audio/video applications. Authored over 20 patents pertaining to the PHY and MAC layers of the system. Played an important role in helping to raise Magis’ A-round of financing
Founder & Owner, Comfocus Corporation 1991-1999
Two-channel maximal-ratio combining full-duplex transciever for the 800 MHz SMR band
Consulting firm focusing on wired and wireless communication systems, including board-level, chip-level and algorithmic system development.
Primary focus on the areas of analog and digital radio communication systems design and subsystem design. Specialization in overall system architecture, digital communication theory, spread spectrum, RF and baseband modems, bit synchronization, digital signal processing, error correction coding, frequency synthesizers, filters, and general RF/analog electronics.See attached appendix for additional detail.
Clients included firms such as Hughes Space & Communications, Linkabit, Hughes Network Systems, Comstream, Conexant , U.S. Air Force, PCSI, AMCC.
Full-Time Employment Prior to 1991:
At Hughes GSG in the 1980’s with the fast synthesizer described in Chapter 6 of my 1994 text
Senior staff engineering positions at General Dynamics, Linkabit, TRW and Hughes
1. Advanced Phase-Lock Techniques, Artech House, 2008.
2. Frequency Synthesizer Design Handbook, Artech House, 1994
3. “Multimedia Over 5 GHz Wireless Home Networks,” Communication Design Conference, San Jose, September 2003
4. “Making OFDM Work for High-Performance Wireless Networking Applications,” April 2003
5. “Sampling Phase-Locked Loops for Frequency Synthesis,” Microwaves & RF, Aug. – Sept. 1984
6. “The Misunderstood Phase/Frequency Detector,” RF Design, Feb. 1985
7. “Synthesizer Designs Minimize Phase Noise in Cellular Systems,” Microwaves & RF, Jan. 1993
8. RAM Mobile Data, “Radio/Modem Reference Design Guide,” Section 3, “DSP Based GMSK Modem Algorithm Design,” Woodbridge NJ , 3 June 1991
9. “Advanced Manpack Radio Concept for UHF DAMA Satellite Communications,” U.S. Air Force Phase I SBIR Final Report, Topic No. AF91-030, Electronics Systems Division, Hanscom AFB, MA, Contract No. F19628-91-C-0154
Additional Project Work
Lead systems architect for a complete family of satellite telemetry, command, and ranging products for commercial satellite users. Responsible for the high-level architecture of both RF and digital signal processing elements. Primary architect for all gate-array and DSP-based signal processing algorithms addressing digital two-way communications (e.g., FSK, QPSK), tone and tone-on-tone ranging, and spread-spectrum based ranging methods.
System engineering for a fiber optics based ultra wideband radar signal interception platform. RF bandwidths in excess of 10 GHz processed using wavelet-based electro-optical techniques.
System engineer for the development of product specifications for an IS-136 ( U.S. advanced digital cellular) RF chip set for a major semiconductor supplier.
Lead RF Systems engineer for a frequency-agile 900 MHz specialized mobile radio (SMR) hand-held product. TDMA, pi/4-DQPSK waveform. Initial production quantity of 100,000 units. Wrote all of the RF system and module performance requirements. Directed a team of RF engineers and technicians from initial conceptualization into manufacturing. Held and directed design reviews. Provided much of the detailed circuit design, and was solely responsible for all of the Mentor-based CAD PWB design for the RF portion. Provided assistance to the digital baseband electronics area related to circuit board layout and EMI mitigation. Also provided assistance with the physical layer digital signal processing algorithms.
Lead RF Systems Engineer for a 225-400 MHz UHF SATCOM radio used for military service. VME card design, high performance requirements (e.g., input third-order intercept point > +5 dBm, LO phase noise < -90 dBc/Hz @ 1 kHz, switching speed < 100 msec to 1 kHz). Personally did all of the low-level detailed design for the receiver portion.
Lead RF Systems Engineer for the development of a dual-mode TDMA commercial telephone in the 450 MHz band compliant with IS-54/55. Performed all of the systems engineering and created a design document of roughly 250 pages for Design Engineering. Provided detailed direction to engineering teams in the U.S. and Taiwan . Monthly manufacturing quantities to be in excess of 20,000 units or more.
Provide RF Systems Engineering for narrow band PCS base station in the 900 MHz band.
Architect for a family of bipolar and CMOS integrated circuits for the wireless communications industry.
Performed a principle role in developing all of the RF system engineering specifications for the CDPD base station (developed by PCSI). This activity included direct day to day involvement and detailed technical direction of engineering staff.
[caption id="attachment_109" align="alignright" width="300"] 5 GHz Yagi antenna element at Magis Networks[/caption]
Complete prototype development including system definition, system analysis, architecture, detailed design, & algorithms for a multi-channel RF link supporting upwards of 35 Mbps in a standard NTSC bandwidth. Included FEC and completely digital adaptive equalizer. This prototype was the forerunner of the emerging 500+ channel television set top decoder. (1991)
Complete conceptualization of the IF and baseband processing for the Navy USTS base station transceiver developed by Titan Linkabit. The design solution made use of RF systems engineering as well as information theory to deal with severe radar pulse interference and other difficult system issues.
Algorithm/hardware design & development for a fully digital UHF SATCOM modem for TDMA OQPSK/BPSK /DPSK modes (Patent awarded January 1994)
Algorithm design & development for a TMS320-based GMSK modem for Mobitex (RAM Mobile Data). Wrote a modem design guide that was distributed by RAM throughout the industry.
Advanced UHF Manpack Concept Study for U.S. Air Force, SBIR Phase I Recipient, Topic AF91-030, Contract No. F19628-91-C-0154, Hanscom AFB. Hardware & software.
System design and detailed design support for a monolithic bipolar data transmitter and data receiver/clock recovery device for Sonet type applications (Data Rates to 1.5 Gbps)
As Founder and owner of ComFocus, developed the first Microsoft Windows based HF and VHF receiver for the consumer market. The product consisted of an external RF unit, which was cabled via RS-232 cable to a DSP board, which an end user would install in their personal computer. All of the DSP software was downloaded from the PC to the DSP board at run time making the product highly reconfigurable. All demodulation, bandpass filtering, AGC, etc. was performed through the DSP. The hardware provided a number of different user personalities including (1) high performance HF receiver with 12 different demodulators, 49 different bandwidths, IF shift, sophisticated blanking, built in real-time spectrum analyzer (2) high speed VHF scanning (> 200 hops per second), (3) wideband spectrum analyzer and (4) an integrated station database and editor for storage of arbitrarily large frequency data base. The product used Analog Devices DSP with the other software layers composed of a C++ DLL and Visual Basic GUI.
About the Author
Excerpts from “About the Author” in Frequency Synthesizer Design Handbook, Artech House, 1994
In previous years, Mr. Crawford has held staff engineering positions at TRW, M/ACOM Linkabit, and Hughes Aircraft Company. While at Hughes Ground Systems Group in the early 1980s, he became group leader for the synthesized frequency sources activities.
Mr. Crawford holds over 30 assigned plus filed U.S. patents in areas including digital signal processing, waveform design, frequency synthesis, and orthogonal frequency division multiplexing (OFDM).
Orignally from a small rural town in southwest Iowa of only 1,000 people, graduating at the top of his “large” class of 36, he has often said that he would not trade growing up in that small town setting for anything. Having made the transition to city life upon heading to college and having spent over 20 years in southern California, it really does ring true that “it is not so much where you are from, but where you are going” that really matters.