The 2023 and 2024 are portable and lightweight synthesized signal generators covering the frequency range 9 kHz to 1.2 GHz (2023) and 9 kHz to 2.4 GHz (2024). A dot matrix display with a comprehensive set of utility menus allow flexibility of operation and ease of use. The RF output can be amplitude, frequency, phase or pulse modulated. An internal programmable AF source is capable of generating simultaneous two-tone modulation. All parameters can be entered from a front panel keyboard and a rotary control can be used to adjust most settings. Microprocessor control ensures that the instruments are flexible and easy to use and allows programming by either the General Purpose Interface Bus (GPIB) or by RS-232. The GPIB is designed to IEEE Standard 488.2. The interfaces allow remote control of all functions except the supply switch, and allow the instruments to be used either manually or as part of a fully automated test system. Main features Operation Selection of parameters on the screen may involve one or more of the numeric, hard or menu selection keys or the rotary control knob. Parameters may be set to specific values by numeric key entry, while values may be varied in steps of any size using the DOWN/UP keys or altered by moving the control knob, set to a particular sensitivity. Display The display is a dot matrix liquid crystal panel, with backlighting. Display contrast may be varied to accommodate differing lighting conditions and the setting saved in memory. A graphical display test is available to the user. Frequency selection Carrier frequency is either selected directly via the keyboard or remotely via the interfaces. Frequency resolution is 1 Hz across the band. A series of carrier frequencies can be stored in nonvolatile memory for recall when required. Output RF output up to +13 dBm can be set by direct keyboard entry with a resolution of 0.1 dB over the entire range. For instruments fitted with the high power option, RF output is increased to +25 dBm. A carrier ON/OFF key is provided to completely disable the output. A choice of level units is available to the user and provision is made for the conversion of units (for example, dBm to μV) by a simple keypress. An electronic trip protects the generator output against reverse power of up to 50 W. This prevents damage to output circuits when RF or DC power is accidentally applied to the RF OUTPUT connector. To facilitate testing of receiver squelch systems, an attenuator hold function allows control of the RF output without introducing RF level drop-outs from the step attenuator. The RF output level can be offset by up to ±5.0 dB to compensate for cable or switching losses, or standardize a group of instruments. Maximum RF output level can be set so as to protect sensitive devices connected to the RF OUTPUT socket. Spectral purity With an SSB phase noise performance of typically -121 dBc/Hz at 20 kHz offset from a 1 GHz carrier, these instruments can be used for both in-channel and adjacent channel receiver measurements. Harmonically related signals and non-harmonics are typically better than -25 dBc and -60 dBc respectively. Calibration This instrument has a recommended two year calibration interval after which it should be returned for recalibration (for addresses refer to 'Addresses' section at end of manual). Modulation Comprehensive amplitude, frequency and phase modulations are available. Pulse modulation can be applied to the carrier from an external pulse source. The instrument also accepts one or two logic level inputs to produce a 2-level or 4-level FSK modulated output. An internal modulation oscillator is provided, having a frequency range of 0.01 Hz to 20 kHz. The oscillator is capable of generating one or two modulation tones simultaneously in one modulation channel. An independent BNC input on the front panel allows external modulation signals to be combined with the internal signal(s). These sources can be combined to give a number of modulation modes. The pulse modulation can be used in combination with the other forms of modulation. The frequency modulation range provides a 1 dB bandwidth of typically 100 kHz and provides FM deviation up to a maximum of 100 kHz. AC or DC coupled FM can be selected. Phase modulation is also available with a 9 kHz bandwidth up to a maximum of 10 radians. Amplitude modulation with a 1 dB bandwidth of typically 30 kHz and with modulation depths of up to 99.9% is available with a resolution of 0.1%. Pulse modulation is available as standard with typical rise and fall times of less than 10 μs and 40 dB on/off ratio. The external input voltage required for 100% modulation is 1 V RMS or, optionally, 1 V peak. To accommodate other signal levels, Automatic Level Control (ALC) can be selected which provides correctly calibrated modulation for inputs between 0.75 and 1.25 V RMS. A MOD ON/OFF key simplifies the testing of signal to noise ratio. An optional fast pulse modulator improves the rise/fall times to typically 10 ns. Incrementing All major parameters can be incremented or decremented in step sizes entered via keyboard entry or remotely. If no step size is entered for a parameter, the steps are preset to 1 kHz for carrier frequency, 1 kHz for modulation oscillator, 1 kHz for FM deviation, 0.1% for AM depth, 0.01 rad for ΦM and 1 dB for output level. In addition, the rotary control knob can be used to vary the parameter with the sensitivity of the knob being changed by means of the ×10 and ÷10 keys. Frequency sweep The sweep capability of the instrument allows comprehensive testing of systems. Sweeps may be logarithmic or linear. Four parameters are used to specify sweep; start, stop, step size and time per step and a percentage increment in the case of logarithmic sweep, all of which may be specified by the user. The sweep can be paused at any time. During the sweep the RF level can be altered using the rotary control. Sweep triggering can be single shot or continuous and can be initiated directly or on the detection of a trigger. The triggering signal may either be programmed or from a TTL signal applied to the rear panel TRIGGER input. Memory The instrument provides both non-volatile and volatile memory for storing instrument settings. The non-volatile memory provides 100 instrument settings and 100 settings of carrier frequency only. The volatile memory (RAM) also provides 100 instrument settings. Any one of the nonvolatile instrument settings can be selected as the power-up setting for the instrument. Memory cloning The stored settings in one instrument can be easily transferred (without the use of a controller) to another instrument using the RS-232 interface, or to several other instruments using the GPIB interface. Memory sequencing A software facility allows sequences of stored instrument settings to be defined. The incrementing facilities can then be used to cycle through the settings in manually operated test systems or be operated via an external trigger. Memory protection To prevent accidental change of the contents of the stored settings, individual memories or ranges of memories can be write-protected. Programming A GPIB interface is fitted so that all functions are controllable via the interface bus which is designed to the IEEE Standard 488.2. The instrument can function both as talker and listener. The instrument also has an RS-232 interface which uses the common GPIB command set. The interfaces enable the instrument to be remotely controlled as well as being used to transfer settings (cloning) from one instrument to another. Calibration data All alignment data is digitally derived. Realignment can be undertaken, without removing covers, by protected front panel functions or via the GPIB interface.