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Option FiltersHOME/PRODUCTS/ACCESSORIES/OPTION FILTERS

Four plug-in filters

Option filters can be installed in the analyzer section of any Audio Precision instrument with analog domain analysis (2700 series, Portable One and ATS-1, and legacy System Two and System One instruments), adding filtering for weighted noise or other special measurements. 2700 series instruments accept up to seven option filters; Portable One and ATS-1 accept up to two. In operation, only one option filter can be selected at a time.

Audio Precision makes a wide variety of Option Filters, including low-pass and high-pass filters, bandpass filters, weighting and other noise measurement filters, sharp cutoff filters, de-emphasis filters and receiver testing filters. We make a “blank” filter circuit card so you can create your own filter, and for 2700 and System Two instruments you can obtain a kit that provides for an external filter connection. If you need a filter that we don't make, contact us and we'd be glad to quote a custom filter for you. 

In addition to the plug-in Option Filters, two special multi-stage filter modules are also available, the S-AES17 Low-Pass Filter and the OPT-2020 Pre-Analyzer filter. Both of these filters have a section that is installed previous to the analog analyzer input, reducing out-of-band noise that may impair the measurement.

Specs

Bandpass Filters 1/3-Octave (Class II) View Graph

Family response: Class II (4-pole)
± 0.2 dB from 0.97 fo to 1.03 fo, < –12 dB at 0.8 fo and 1.25 fo, < –32 dB at 0.5 fo and 2.0 fo. These filters permit measuring specific frequencies in the presence of white noise. Contact Audio Precision if you have requirements for filter frequencies not listed here. 

  • FBP-120  Bandpass Filter  fo = 120 Hz
  • FBP-180  Bandpass Filter  fo = 180 Hz  
  • FBP-250  Bandpass Filter  fo = 250 Hz
  • FBP-300  Bandpass Filter  fo = 300 Hz 
  • FBP-400  Bandpass Filter  fo = 400 Hz  
  • FBP-500  Bandpass Filter  fo = 500 Hz
  • FBP-500HQ  Bandpass Filter (Hi-Q) fo = 500 Hz (for linearity measurements) 
  • FBP-600  Bandpass Filter  fo = 600 Hz  
  • FBP-666  Bandpass Filter  fo = 666 Hz  
  • FBP-800  Bandpass Filter  fo = 800 Hz  
  • FBP-945  Bandpass Filter  fo = 945 Hz  
  • FBP-1000  Bandpass Filter  fo = 1.00 kHz 
  • FBP-1200  Bandpass Filter  fo = 1.20 kHz  
  • FBP-1500  Bandpass Filter  fo = 1.50 kHz  
  • FBP-2000  Bandpass Filter  fo = 2.00 kHz  
  • FBP-3000  Bandpass Filter  fo = 3.00 kHz  
  • FBP-3150  Bandpass Filter  fo = 3.15 kHz  
  • FBP-4000  Bandpass Filter  fo = 4.00 kHz  
  • FBP-4500  Bandpass Filter  fo = 4.50 kHz
  • FBP-5000  Bandpass Filter  fo = 5.00 kHz  
  • FBP-6000  Bandpass Filter  fo = 6.00 kHz  
  • FBP-8000  Bandpass Filter  fo = 8.00 kHz  
  • FBP-10000  Bandpass Filter  fo = 10.0 kHz  
  • FBP-12500  Bandpass Filter  fo = 12.5 kHz  
  • FBP-15000  Bandpass Filter  fo = 15.0 kHz  
  • FBP-16000  Bandpass Filter  fo = 16.0 kHz  
  • FBP-20000  Bandpass Filter  fo = 20.0 kHz  
  • FBP-22000  Bandpass Filter  fo = 22.0 kHz

Low-pass Filters (bandwidth-limiting)

  • FLP-300  Low-Pass Filter  300 Hz ± 3%, 5-pole Butterworth
  • FLP-400  Low-Pass Filter  400 Hz ± 3%, 5-pole Butterworth
  • FLP-500 Low-Pass Filter  500 Hz ± 3%, 5-pole Butterworth
  • FLP-1K  Low-Pass Filter  1 kHz ± 3%, 5-pole Butterworth View Graph 
  • FLP-3K  Low-Pass Filter  3 kHz ± 3%, 7-pole Butterworth
  • FLP-4K  Low-Pass Filter  4 kHz ± 3%, 7-pole Butterworth
  • FLP-8K  Low-Pass Filter  8 kHz ± 3%, 7-pole Butterworth View Graph
  • FLP-12.7k-1  Low-Pass 12.7 kHz, 1-pole Butterworth 
  • FLP-20K Low-Pass Filter  20 kHz ± 3%, (per AES-17)
  • FLP-50K Low-Pass Filter  50 kHz ± 5%, 3-pole Butterworth View Graph

High-pass Filters (bandwidth-limiting)

  • FHP-70  Bandwidth-Limiting, High-Pass Filter  70 Hz ± 3%, 8-pole
  • FHP-400  Bandwidth-Limiting, High-Pass Filter  400 Hz ± 3%, 9-pole View Graph
  • FHP-2K  Bandwidth-Limiting, High-Pass Filter  2 kHz ± 3%, 9-pole

De-emphasis Filters

  • FIL-D50 De-emphasis Filter 50 µs ± 1% View Graph
  • FIL-D50E De-emphasis Filter 50 µs ± 1% + 15.625 kHz notch
  • FIL-D50F De-emphasis Filter 50 µs ± 1% + 19.0 kHz notch View Graph
  • FIL-D75 De-emphasis Filter 75 µs ± 1% View Graph
  • FIL-D75B De-emphasis Filter 75 µs ± 1% + 15.734 kHz notch
  • FIL-D75F De-emphasis Filter 75 µs ± 1% + 19.0 kHz notch

Weighting and Noise Measurement Filters

  • FIL-AWT  Noise Measurement Filter  “A” weighting per IEC Standard 61672-1 (2002) (Replacement for previous standard 179 and 651) View Graph
  • FIL-CCR  Noise Measurement Filter  Weighting per CCIR Rec 468 and DIN 45404 (Also for CCIR/ARM) View Graph
  • FIL-CIT  Noise Measurement Filter  Weighting per CCITT Rec P53 View Graph
  • FIL-CMS  Noise Measurement Filter  “C-message” per BSTM 41004 and ANSI/IEEE Std 743-1984 View Graph
  • FIL-CWT  Noise Measurement Filter  “C” weighting per IEC Rec 179 View Graph

Receiver Testing Filters

  • FIL-RCR  Receiver Test Filter  200 Hz–15 kHz + 19.0 kHz notch
  • FIL-FMP  15 kHz low-pass filter + 19 kHz notch filter.
  • FIL-IECR  Receiver Test Filter  20 Hz-15 kHz + 15.625 kHz notch View Graph
  • FIL-VID  De-emphasis Filter  12.6 kHz sharp low pass filter with notch at 15.7 kHz to reject the Hsync pilot tone in TV stereo

Miscellaneous Option Filters

  • FBP-500X Bandpass Filter. High-Q 500 Hz bandpass for CD DAC linearity measurements. View Graph
  • FLP-B20K 20 kHz “Brickwall” Filter. The FLP-B20K filter offers negligible effect below 20 kHz, but very high attenuation above. Its purpose is to remove sampling frequencies, typically 44.1 kHz or higher, as well as switching components.
  • FLP-B40K 40 kHz “Brickwall” Filter. Similar in purpose to FLP-B20K, but with knee at 40 kHz, typically used for removing sampling frequencies at 88.1 kHz, 96 kHz or higher. 
  • FIL-USR User-buildable Filter. This blank circuit board with connector allows building building custom active or passive filters.
  • System Two External Filter. This kit allows a user-designed filter to be connected externally to a 2700 series or System Two instrument.

 

 

 


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