Single Function Instruments
BR-640A Manually Controlled Broadband RF Receiver
The BR-640A is a modestly high gain broadband RF receiver specifically designed for use in ultrasonic systems. It features a bandwidth extending from 100 kHz to 50 MHz with an adjustable gain of -12 to 64 dB. It has a low noise figure with both high and low input impedances plus selectable high and low pass filters for bandwidth control. The BR-640A has fast recovery while still being protected against severe overload, allowing its use in a pulse echo (single transducer) type of operation.
SP-801A Manually Controlled High Power Square Wave Pulser
The SP-801A produces negative high power square pulses with fast rise and fall times with an extremely low output impedance (~ 4 Ohms). The pulse width can be precisely matched (continuously variable) to the half period of the frequency (50 kHz to 20 MHz with four adjustable ranges) of an ultrasonic transducer. This maximizes the energy transfer and signal-to-noise ratio for a given voltage output and is, therefore, significantly more effective than a spike pulser. This is especially true at low frequencies. The output level is adjustable in 2-dB steps, from -400 Volts down to -50 Volts.
GA-2500A High Power Gated RF Pulse Amplifier
The GA-2500A is a limited-duty cycle amplifier producing high-power RF tone bursts derived from either a continuous-wave (CW) source or an externally generated low-level (~1 Volt peak-to-peak) tone burst. In addition to the RF input, a coherent gate (TTL/CMOS) is required to turn the amplifier on. Two different versions are available depending on the polarity of the coherent gate. The standard GA-2500A uses a positive TTL gate (high during the on time and low during the off time) similar to those produced by the Stanford Research Systems DS-345 function generator. The GA-2500A-NG uses a TTL gate which is high during the off time and low during the on time. This type gate is produced by the Agilent 33120A function generator. The power output is continuously adjustable by a front panel potentiometer. Three versions of the instrument are available with different maximum output levels: 5 KW, 1.5 KW, and 400 W root mean squared (RMS) power into 50 Ohms during the burst. The frequency span of each amplifier is tailored to meet the user's needs within the range of 40 kHz to 20 MHz.