Agilent / HP 8757A

The 8757A is a microprocessor-based receiver capable of making scalar (magnitude only) reflection and transmission measurements over a frequency range determined by the external detectors used. It has a large screen for display of measurement results. It is programmable over the Hewlett-Packard Interface Bus (HP-IB). Whether or not the 8757A is controlled remotely over HP-IB, it can control a specific plotter and/or source throught the 8757 system interface. A measurement with the 8757A requires the connection of detector(s) and/or directional bridge(s) to the detector input on the front panel, and the use of a compatible RF/microwave source.

The 8757A is locally operated by front panel controls and by menu selection using "soft" keys adjacent to the CRT. It has four independent but identical measurement channels, allowing simultaneous viewing of up to four measurement parameters with independent resolutions. The standard instrument has three detector inputs while Option 001 has four detector inputs. The 8757A uses either AC or DC detection techniques in conjunction with its detectors. AC detection provides very stable measurements even with temperature variations and RF interference. DC detection should be used for modulation-sensitive devices (for example, non-linear amplifiers, narrow-band filters) and for devices that cannot be modulated (for example, oscillators).

• Four independent display channels
• Three inputs (four with Option 001)
• Dynamic range:
  • With 11664A/E detector: +16 to ‑60 dBm
  • With 11664D detector: +10 to ‑50 dBm
  • With 85025A/B detector: +16 to ‑55 dBm (AC mode), +16 to ‑50 dBm (DC mode)
• Sweep time (1, 2, 3, 4 traces) - Minimum sweep time and maximum number of display traces depend on horizontal resolution:
  • 101 points: 40, 50, 60, 70 ms
  • 201 pionts: 50, 75, 90, 100 ms
  • 401 points: 100, 100, 150, 200 ms
  • 801 points: 200, 250, N/A, N/A ms
  • 1601 points: 400, N/A, N/A, N/A ms
• Sweep voltage (Sweep in): 0 to 10 V
• Marker and Blanking typical voltage levels:
  • Blanked: +5 V
  • Unblanked: 0 V
  • Marker: -4 V
  • Active marker: -8 V
• Scale resolution (independently controlled for each channel): 0.1, 0.2, 0.5, 1, 2, 5, 10, 20 dB per division
• Reference offset: ‑70 to +20 dBm (power), ‑90 to +90 dB (ratio)
• Display resolution:
  • Vertical: 0.003 dB single input, 0.006 dB ratio measurement, 0.01 dB "Display Cursor"
  • Horizontal: 101, 201, 401, 801, 1601 data points
• Averaging: 2, 4, 8, 16, 32, 64, 128, 256 successive traces may be averaged
• Smoothing: 0.1% to 20% of the trace width
• Rear panel connectors: Stop Sweep, DAC Out, ADC In
• HP-IB interface
• Interface function codes: SH1, AH1, T6, TE0, L4, LE0, SR1, RL1, PP0, DC1, DT0, C0, E1
• Transfer formats: ASCII strings, 16-bit integers
• Programmable functions: All front panel functions, except power and CRT
• SRQs (service interrupts): Front panel key pressed, soft key only pressed, operation complete (sweep or plot), syntax error, instrument self-test error, numeric entry completed, limit test failed, action requested not possible, knob activity, low battery voltage