Source Locking CW Microwave Frequency Counters with Selective Power Measurement

The 575B and 578B CW frequency counters are distinguished by their fully automatic source-locking capability. Virtually any electronically tunable frequency source can be locked to the same accuracy and long-term stability as the time base oscillators inside the 575B and 578B. The ability of these counters to accurately set and stabilize the frequency of a basic frequency source can many times save the expense of a synthesized signal generator. The locked frequency is settable in 10 kHz increments from 10 MHz to the maximum frequency of the counter. The 20 GHz 575B and the 26.5 GHz 578B (110 GHz optional) are fully programmable via GPIB thereby making the locked source an easily integrated par of an ATE system.

All Phase Matrix EIP® brand frequency counters are based on a unique heterodyne architecture that incorporates a YIG-based preselector. The YIG-preselected input provides unparalleled performance, in amplitude discrimination, frequency selectivity, kickback noise, and burnout protection.

  • Source Locking (from 10 MHz to as high as the counter’s max. frequency)
  • Laser frequency control
  • Frequency Limits for Selective Frequency and Power Measurements, limits are controlled by keyboard
  • -30 dBm sensitivity
  • Power Measurements to ±0.1 dB resolution, ±0.5 dB accuracy (typ.)
  • Optional Frequency Extension to 110 GHz (578B Only)
  • 10 dB automatic amplitude discrimination
  • 200 msec acquisition time
  • Up to 800 MHz/sec tracking speed
  • 20 MHz P-P FM tolerance up to a 10 MHz rate
  • 200W (+53 dBm) peak damage protection

Unsurpassed Burnout Protection

Typically found in high performance spectrum analyzers; only Phase Matrix counters feature a YIG-preselected microwave input, which provides unparralled burnout protection, FM tolerance and frequency selectivity. The YIG preselector works like a tunable bandpass filter, preventing harmonics and other out-of-band spurious signals from interfering with measurement of the desired signal. It also protects the counter from accidental application of high level signals (up to 200 watts peak), reducing downtime and the associated high cost of repairing damaged microwave circuitry.

Selective Frequency and Power Measurements

With a single connection, the 575B and 578B can simultaneously measure and display the input signals frequency and power level in the microwave band, eliminating the need for a seperate microwave power meter. Within the 25MHz bandwidth of the YIG-preselector, only the selected signals frequency and power level are measured. Signals to be analyzed are selected by keystroke entry of an individual center frequency, or search a range between a low and high frquency limit. This signal selectivity, combined with 20MHz of FM tolerance at all rates up to 10MHz, allows the 575B and the 578B to make accurate frequency and power level measurements even while the input signal is carrying traffic.

Frequency Extension to 110 GHz

Option 06 provides the ability to extend the frequency range of your 578B, in bands, up to 110 GHz. Remote sensors allow you to reach out to connect to virtually any wave guide system without the complications of the additional plumbing necessary to bring the signal to your counter. A wide selection of sensors provides measurement capability in the wave guide band that you are working in now, and the flexibility to change as your application changes without having to purchase another counter.

New Flexibility For GPIB-based ATE Systems

The Phase Matrix 575B/578B family of counters offers new flexibility and efficiency in controller programming of your source. First, programming steps can be eliminated by letting the counter directly control the sources frequency over its entire frequency range. Second, only a single command string to the counter is needed to set and lock the source. Third, the signal source does not need to have GPIB capability. The counter constantly monitors and corrects the source thereby relieving the controller of the task of checking the frequency and issuing correction commands. The ability to rapidly step and lock the signal source also saves test time as shown by these examples:

Frequency Step / Typical Lock Time:

  • 1 MHz / <200 ms
  • 10 MHz / <300 ms
  • 1 GHz / <500 ms

Automatic Broad-Band Tuning

Operation of the source and counter combination is straightforward and automatic. Lock frequency is easily entered via the front panel keyboard or via standard GPIB interface. The counter automatically takes it from there, locking the source at the entered frequency. Frequency Storage and Recall For repetitive production testing, an operator can store up to nine lock frequencies and rapidly recall them as needed. This also reduces typical lock times for steps over 10 MHz to<300ms.

Frequency Limits

Automatic amplitude discrimination enables the 575B/578B counters to automatically select and measure the input signal with the highest level, and ignore all other harmonics and other spurious signals that are present. “Frequency Limits” extend this signal selection capability by allowing you to select upper and lower limits, The counter will measure the frequency and power level of only the highest level signal within these limits – even if there are higher level signals present at the counters input. This gives you the ability to measure the frequency and power of a low level signal (such as a harmonic) even when a signal of much higher level (the fundamental) is present.

Power Measurement

The 575B/578B family of microwave counters offers the optional ability to simultaneously measure both the frequency and power level through the same input. This often eliminates the need for a separate microwave power meter. With the 25 MHz bandwidth of the YIG tuned preselector, power measurement is made only of the displayed signal, not of its harmonics or other signals present. Thus you can simultaneously measure and display both frequency and power of individual signals in a multisignal environment. Easy keystroke entry of power offsets can be used to measure power deviation from a reference, or to compensate for losses in external hook-ups such as cable and attenuator losses.