May 19, 2011

ZTEC Announces I/Q Digitizer optimized for OFDM Testing (WiFi, WiMAX & LTE)

Albuquerque, NM.– ZTEC Instruments (, announced that they have released the next instrument in the Company’s RF & Wireless Communication product line. The ZT8450 I/Q Digitizer functions as a baseband Vector Signal Analyzer (VSA) from DC to 300 MHz.  This new baseband VSA provides the signal fidelity and real-time processing capabilities that enable a broad set of necessary RF and wireless test techniques, such as performing EVM (error vector magnitude), ACLR (adjacent channel leakage ratio) and IM3 (3rd-order intermodulation distortion) measurements or addressing complex MIMO applications.  The ZT8450 provides the combination of high instantaneous bandwidth, high dynamic range, very high linearity, and very low phase noise necessary to test and characterize the latest and next generation of RFIC components.

Key specifications of the ZT8450 I/Q Digitizers include:
  • VSA functionality including demodulation of OFDM waveforms (802.11a/n/ac WiFi, WiMAX & LTE)
  • VSA measurement toolkit including EVM, ACLR and IM3
  • Two differential inputs (I/Q or Dual IF)
  • Two 14 bit 400 MS/s ADCs
  • 512 MB deep memory
  • 300 MHz analog bandwidth
  • Programmable I/Q input gain of 0 dB to 30 dB
  • On-board Digital Downconverter (DDC) with fractional re-sampling
  • Programmable un-aliased DDC instantaneous bandwidth up to 160 MHz
  • Available in 2 or 4 channels in PXI, PCI, VXI and LXI

The ZT8450 I/Q Digitizers expand upon ZTEC’s existing ZT8440 IF Digitizers by adding differential baseband I/Q input functionality.  Whereas the ZT8440 series is most suited as an IF processing engine in combination with an RF Downconverter, the ZT8450 series is optimized for differential I/Q testing of baseband RFIC components.  Differences between the two instruments are summarized in the following table:

IF Digitizer
Differential I/Q Digitizer
Input Channels
2 single-ended
2 differential
Input Ranges
+10dBm, 0dBm, -10dBm, -20dBm
Input Bandwidth
DC to 1 GHz
DC to 300 MHz
72.7 dBFS (+10dBm)
79.7 dBFS (+10dBm)
Phase Noise
(Internal Clock)
<-100 dBc/Hz @ 1 kHz offset
<-105 dBc/Hz @ 10 kHz offset
<-118 dBc/Hz @ 100 kHz offset
<-115 dBc/Hz @ 1 kHz offset
<-140 dBc/Hz @ 10 kHz offset
<-150 dBc/Hz @ 100 kHz offset
External ADC Clock

The targeted use-cases for the two instruments explain the feature differences:
  • The ZT8440 series is best suited as an IF digitizer for use with an RF Downconverter.  The IF input power level to the ZT8440 is fixed because the range scaling is provided by the RF Downconverter, prior to mixing down to IF.  Also, the RF Downconverter often has a high-quality clock output that can be applied as the external ADC clock input on the ZT8440 IF digitizer for optimum phase noise performance.
  • The ZT8450 series is optimized for stand-alone differential I/Q testing of baseband RFIC components such as I/Q Demodulators.  Many demodulator RFICs have differential I/Q outputs, and many need to be tested at Zero IF or baseband frequencies. The 0dB to 30dB of programmable gain on the I/Q inputs enables the ZT8450 to amplify very small I/Q signals while maintaining good noise figure.  Finally, a high-quality internal ADC clock provides extremely low phase noise.

About ZTEC Instruments
ZTEC Instruments is a leading modular instrument company whose product focus includes oscilloscopes, waveform generators, and RF & wireless communication test equipment. ZTEC Instruments’ products are unique in that they provide powerful bench-top instrument capabilities in modular instrument form factors, including PCI, Compact PCI/PXI, VXI, and LXI. For more information about ZTEC Instruments please visit