Advantest U3661 Spectrum Analyzer

For Field Maintenance of Microwave Radio Facilities and Digital Mobile Communication

Features

• Frequency Range: 9 kHz to 26.5 GHz
• Ultra-compact and Light Weight (Main Unit: 8.5 kg or Less; with Battery: 10.8 kg or Less)
• Display Dynamic Range: 100 dB
• Three-way Power Supply with Battery Operation
• (100/200 VAC, External DC and Battery Pack)
• 1-hour Operation Is Possible with the Specialized Battery
• TFT 6-inch Color LCD and Memory Card
• High-stability Measurement by Means of Synthesized Operation
• 50-µs High-speed Sweep Function
• Diverse Options Including:
• TV Video/Audio Demodulation
• Tracking Generator
• High-stability Reference Source
• Narrow RBW
• Channel Input Setting
• CDMA Setting
• Variety of Measurement Functions
• Adjacent-channel Leakage Power
• Audio Monitoring

Applications

• Field Maintenance of Microwave Links
• Installation and Maintenance of Digital Radio Facilities
• TV/Broadcast Maintenance
• Measurement of: ACP, OBW

The radio communication field is undergoing fast growth on a global scale, expanding the frequency band usage across the spectrum from the microwave to the millimeter-wave bands. The U3661, at 8.5 kg, is the lightest weight microwave spectrum analyzer in the world.*¹ It accommodates the diverse needs of these various communication systems. As well as enhanced basic performance as a spectrum analyzer, the U3661 is equipped with many standard functions such as power calculation and high-speed sweep.

The compact, lightweight design of the U3661 utilizes a three-way power source system which includes a battery; it is an optimum analyzer for field measurement. This unit also has a built-in RS232 interface for a personal computer, facilitating flexible data management using standard memory cards.

*¹ April 1998.

Full Range of Features for Portability and Application Support

The U3661 is light and compact (8.5 kg or less without the battery pack or 10.8 kg or less with the pack). The easy-to-attach strap allows the analyzer to be worn on the shoulder and easily carried.

The U3661 is rugged enough to satisfy the requirements of vibration, shock and drop tests, allowing them to be used safely under harsh field conditions.

The U3661 operates not only on 100/200 VAC power but also on +10 to +16 VDC power or the Battery Pack. The Battery Pack allows 1 hour continuous operation at a full charge, making it easier to perform logistically wide-ranging measurements such as maintenance and installation work. It features a rapid two hour battery charging time.

Large Color TFT LC Display

The U3661 employs a 6 in. color TFT LCD display and a tilt mechanism that allows an angle of ±15 degrees, remarkably improving the visibility and efficiency of analysis work.

2-Slots Memory Card Drive

Having two memory card drives conforming to JEIDA-Ver. 4.1/PCMCIA Rel. 2.0 as standard, measurement condition setup and data recording can be performed while two memory cards are loaded in the drives. There are three different record formats for memory card: binary, bitmap and text (CSV). In particular, the text (CSV) format is handy for data analysis and report creation using spreadsheet software on a personal computer.

Wide Array of Analysis Functions

Along with basic functions such as a frequency counter with a 1 Hz resolution and a 20 dB gain preamplifier, the U3661 comes standardly equipped with analysis functions for measuring items such as dB down, third order intermodulation distortion, AM modulation, occupied bandwidth and adjacent channel leakage power. GO-NO GO evaluations of the displayed waveform can also be easily performed using the limit line and PASS/FAIL functions which allow upper and lower limits to be set on the screen.

Example of PASS/FAIL evaluation.

Selectable Data Save Format

When the standard installed memory card is used, data can be stored in three types of data formats.

SAVE Item Display.

All measurement conditions and waveform data are stored on the memory card. The stored data can be reproduced on the U3661. Multiple measurement conditions can be saved, and can be recalled at any time. Thus, complicated operations may be repeated automatically by simplified recall from memory. The saved measurement conditions can also be utilized to manage a large amount of waveform data.

The data stored in CSV format can be directly read on a PC. For example, if a CSV file is opened with spreadsheet software on the PC, measurement data can be edited and managed on the PC.

Spreadsheet Software (CSV Format) and Image Edit Software (BITMAP Format).

COPY in BITMAP Format

Basically, this function outputs a screen image directly to the printer or plotter. However, when the memory card is specified for the copy target, the graphic image data from the screen is saved on the memory card in BITMAP format. This data file can also be opened on a PC for managing screen image files.

* The data stored in CSV or BITMAP format cannot be reproduced on the U3661 main unit.

Excellent Basic Performance and Measurement Applications

The U3661 can continuously sweep the frequency bandwidth from 9 kHz to 26.5 GHz on a single screen. It enables easy relative comparison with the basic wave for harmonic measurements in a wide band or for spurious signal measurement.

Occupied Frequency Bandwidth

The U3661 calculates the bandwidth for the specified power ratio from measured spectrum data and then displays it with the marker. In addition, it displays the occupied frequency bandwidth (OBW) and carrier frequency (FC).

Excellent Signal Purity

Equipped with a precise synthesizer, the local oscillator of the U3661 achieves a signal purity of -100 dBc/Hz (frequency <3.2 GHz, at 10 kHz offset frequency). The unit accommodates wide-ranging needs from adjacent channel leakage power measurements of radio facilities to microwave device evaluation.

Adjacent-channel Leakage Power

The U3661 obtains the total power from the measured data on the screen. Then it integrates the power with respect to the specified bandwidth (BS) to obtain its ratio to total power. ACP POINT and ACP GRAPH measurement methods can be selected.

Varied Measurement Applications

Power Measurement Functions

Average Power

The modulation modes used for digital mobile communication systems handle signals with large amplitude variation. Therefore, an average power calculation function is incorporated, allowing power measurement for signals with amplitude variation.

Total Power

For Spread spectrum signals, used in CDMA or wireless LAN, the total power measurement function is crucial. This function includes two modes: one is the channel mode which measures the in-band power specified from the measuring window and the other is the total power mode which measures the total power over the entire measurement span.

1 Hz Resolution Frequency Counter

Just by adjusting the counter marker to the spectrum, the U3661 can display a frequency counter with a minimum resolution of 1 Hz. This function is extremely useful in multi-carrier frequency measurements, such as mobile radio or CATV systems, which are difficult with conventional frequency counters.

Multi-marker

Up to six markers can be set on a single screen, with the respective markers specified for any frequency. The multi-marker function enables automatic detection of peaks and displays a frequency list ordered by either level or frequency.

Pre-Amp 20 dB Gain

Equipped with pre-amp gain of 20 dB or more for bandwidths ranging from 9 kHz to 3.2 GHz, even very weak signals of -130 dBm or less can be analyzed. Since level calibration is also executed within the bandwidth when the pre-amp is turned ON, the measured level can be directly read.

Gated Sweep

The U3661 can perform spectral analysis of bursted signals utilizing an external trigger signal. The trigger synchronizing the burst measurement is applied to the "GATE IN" connector on the rear panel. In addition, the gate position and gate width timing can be generated with the external input trigger signal as the start point, so that the gated sweep range on the time axis can be set for the burst signal.

Gated Sweep OFF.

Gated Sweep ON.

50 µs High-speed Sweep Function

In ZERO SPAN mode (fixed tuning mode without frequency sweep), the sweep time can be set up to 50 µs. This makes it possible to observe TDMA waveforms for digital mobile communication systems and perform detailed analysis through magnified display of burst rising and falling waveforms.

Ideal For Analysis of TV Transmissions

Opt. 72 - TV Demodulation.

Video/Audio Demodulation

The PICTURE KEY switches from a spectrum display to a TV image display. Sound demodulation is provided simultaneously to compare easily the spectrum waveform and the images. The equipment can be used as a demodulator for arbitrary frequencies as in a TV relay station's IF bands or CATV uplink image checking.

TV picture demodulation.

TV Channel Input

Selecting the TV KEY provides channel input frequency tuning. VHF, UHF, CATV, BS and CS channel tables are prestored in the base memory, and these tables can be customized by users. The marker function allows channel band display as well as frequency/level indication.

Conforms with World TV Standards

TV demodulation option (Opt. 72) covers worldwide TV standards: NTSC, PAL and SECAM colors and M, B/G, D/K/K', I and L/L' systems are selectable.

Tracking Generator for Filter Evaluation, Loss Measurement

Opt. 74 - Tracking Generator.

Frequency Characteristics Evaluations of Filters and Amplifiers

Tracking generator option (Opt. 74) can generate a sine wave signal in synch to the frequency sweep of a spectrum analyzer in a range of 100 kHz to 2.2 GHz, enabling direct measurement of frequency characteristics.

Example of band pass filter measurement.

Impedance Matching Measurement

With a SWR bridge (optional accessory), Tracking generator option (Opt. 74) can measure return loss, enabling simple evaluation of DUT impedance matching.

Recommended SWR Bridge: ZRB2VAR-52/53/73 (ROHDE&SCHWARZ).

Circuit Network Loss Measurement

Tracking generator option (Opt. 74) can easily measure the insertion loss of high frequency devices and equipment, or their connected cables, in a wide frequency range of 100 kHz to 2.2 GHz.

Normalization Function Enables High Precision Measurement

When used with a tracking generator, tracking generator option (Opt. 74) has a normalization function which cancels out all frequency characteristics of the measuring devices. This function allows characteristics evaluation to be made of only the DUT.

The U3661 Allows Channel Setting for Communication Systems of Major Countries

Opt. 78 - Channel input setting.

Most communication systems employ the FDMA (Frequency Division Multiple Access) method. When observing the signals using the U3661, each carrier frequency band to be measured can be registered in the built-in table as a user channel. This allows the center frequency to be called by means of the channel number, resulting in improved work efficiency.

Channel numbers from 1 to 99 can be registered and two tables are provided. For TV broadcasting wave, frequencies are preset according to the VHF, UHF, CATV BS and CS band designations of major countries.

(Opt. 78 is included in Opt. 72.)

CDMA Option

Opt. 60 - CDMA Measurement.

When the CMDA option (Opt. 60) is added to the U3661, the CDMA transmission characteristic specified by Standard IS-95 and J-STD-008 can be measured in a single operation.

Features

• Automatic internal setting of CDMA parameters
• Frequency tuning setting by channel number
• High-stability CDMA channel power measurement function
• High-sensitivity power measurement by the built-in pre-amp

Measurement Items

• Channel power measurement
• OBW measurement
• ACP (spectrum mask) measurement
• Spurious emission (in-band) measurement

Channel power measurement.

ACP Measurement.