Abstract: An apparatus and method for calibrating a yttrium-iron-garnet-tuned filter (YTF) is disclosed. Instead of using both tune+span information from the 1st LO, only the sweep ramp used to span the 1st LO is used for the YTF's s own swept spans, and the YTF has its own tune information created independently of tune of the YIG oscillator. This allows calibration at any time, both in the factory or in the field.

Abstract: A bus system is disclosed in which stations having a message to send request access to a parallel bus and an arbitrator responding to the requests connects the transmitters of the stations to the bus in sequence. The words of a message placed on the bus respectively represent the address of the station to which the message is to be delivered, the address of the sending station, and data. A station asserts a signal on one control line in response to its address being on the bus and asserts a signal on another control line if it cannot receive a message. Whether the entire message is placed on the bus or not by the sending station and loaded into the registers of the receiving station depends on whether or not their signals are asserted. An external data transfer means places signals to a station on another parallel bus on an external bus. The external bus is in the form of a loop so that the message eventually returns to the station that sent it.

Abstract: An automatic spectrum analyzer is provided with enhanced features for measured data handling and analysis. One feature allows the user to establish a sequence of operations to be performed at the end of each sweep of the instrument. Another feature enables the user to specify a particular signal amplitude and to have a marker placed on a displayed signal trace at that amplitude. Still another feature provides a marker that can be positioned on the next signal peak to the right or the left of the current marker position, enabling the display of the amplitude and frequency of the signal on which the marker is placed.

Abstract: An automatic spectrum analyzer is provided with enhanced features for measured data handling and analysis. One feature allows the user to establish a sequence of operations to be performed at the end of each sweep of the instrument. Another feature enables the user to specify a particular signal amplitude and to have a marker placed on a displayed signal trace at that amplitude. Still another feature provides a marker that can be positioned on the next signal peak to the right or the left of the current marker position, enabling the display of the amplitude and frequency of the signal on which the marker is placed.

Abstract: An input signal is mixed with sampling signals from oscillators which vary the frequency of the sampling signal from a first frequency to a second frequency. The resulting Intermediate Frequency (IF) signal is processed and digital values are stored in a memory in response thereto. Waveforms are then displayed which correspond to these frequency and amplitude values. Various input and display circuits facilitate the display and interpretation of these waveforms.