APN 02 Generator – 1 Hz to 260 kHz, synthesizer, output configurations: balanced floating, balanced grounded, unbalanced.
APN 04 – Like the APN 02, but with integral voltmeter for measuring the output voltage or external voltages. It has a remote-control interface to lEC 625 – 1 and IEEE 488.
APN 06 – Like the APN 02, but with square signal in the frequency range 1 Hz to 260 kHz and variable level. It has a remote-control interface to lEC 625 – 1 and IEEE 488.
Option APN-B1 provides reference-frequency input/output for external synchronization and to obtain an output voltage proportional to frequency or level .
The APN series frequency generation is completely digital. The output signal has crystal accuracy, high frequency resolution and fast phase-continuous frequency adjustments without transients. All these features make possible a sweep which is indistinguishable from a true analog sweep. Thanks to the high frequency resolution of 1 Hz over the whole range and 0.1 Hz in the range below 20 kHz, measurements on extra narrow bandwidth DUTs such as crystal filters are possible. The 0.1 Hz resoluhon allows the use of tone sequences to all known standards. Error-free measurements on filters with steep skirts or on narrowband DUTs are only possible if frequency adjustments are phase-continuous – this is the case with the APN.
The output signal is generated by means of D/A conversion so ensuring an extremely high level accuracy. Because of the low minimum level, all the levels likely to be required in practice can be obtained without the use of external attenuators. For checking the lineanty of amplifiers and for dynamic tests on ALC circuits, the signal can be swept over 20 dB without interrupting Ihe level. The start and stop level, the step size and the step time are selectable The output level can be set in V, dBV, dBu or dBm.
Over the whole of the audio range to 20 kHz, distortion is below 0.05 % ; up to 100 kHz it is below 0.1 %. When a DUT requires a balanced feed, the exact balance of the two signal components is of utmost importance. The fully balanced design of the two output signal branches ensures this. The unbalance caused by residual signals Is more than 60 dB below the set signal level.
The APNs source impedance can be set to any value between 10 ohm and 640 ohm in 5-ohm steps and so covers practically the complete range of system impedances.
The APNs output signal can be balanced floating, balanced grounded or unbalanced grounded. Balanced signals are required for telephone systems and acoustic measurements.
Additional features of models APN 04 and APN 06:
When a level is entered. the level shown by the display is only the same as the level across the load when the load impedance is equal to the source Impedance. If the load impedance Is not known. the voltage drop must be measured. Using the APN 04s integral voltmeter (true RMS. AUTO RANGE. RANGE HOLD), the display always shows the true load-dependent output voltage. The voltmeter has its own Input for measuring external voltages.
To process the results using analog methods. a voltage which is proportional to the result Is output. Numerical processing can be performed using the lEC bus in talker mode. Thanks to its integrated test functions, the APN 04 is an ideal, handy AF test set for determining the transmission characteristics of AF paths and control systems.
As well as sinusoids. the APN 06 can generate square signals whose level can be adjusted. These signals are output at a separate connector. The unit is also Ideal as a stimulus for bipolar logic. for use in digital control systems and for overload measurements on analog devices.
The APN62 is a modified version of the APN06 with an output transformer and different AC supply voltage ranges.