Tektronix AF501 Bandpass Filter
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$62.01 8/24/01 #1628569048 bbg|
$58.00 11/2/01 #1654097093 dolemite77
$61.00 3/16/02 #1712298054 worldmike
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$90.78 (+$12 ship) 1/6/08 #280189273159 surplusauctions (12 bids $4.99 start) (untested)
The AF 501 Bandpass Filter/Amplifier is an active filter whose center frequency is one-knob tunable over the entire audio range from 3 Hz to 35 kHz. Broad (Q = 5) and narrow (Q = 15) bandwidths are switch selectable. Flat amplification to 50 kHz is also available. In both filter and flat modes, amplification from 1 to 500 may be selected in a 1-2-5 sequence. The AF 501 also features an oscillator mode where the output frequency is the same as the center-tuned frequency in the filter modes. The AF 501 selectivity permits individual analysis of the fundamental and harmonic components of complex waveforms, such as signals from vibration transducers.
The AF 501 was developed primarily for the mechanical measurement domain. The AF 501 can be used as a manual-sweep spectrum analyzer for complex sound and vibration signals. Single-frequency tuning facilitates isolation of 1X rpm signals in dynamic balancing, or viewing higher order disturbances on a crt monitor. An output pulse, synced to the filter or oscillator output signal, is available for triggering a stoboscope or oscilloscope and for frequency counting. And, of course, the AF 501 can be used in any application calling for a conventional sine-wave generator, ac coupled amplifier, or bandpass filter.
A single knob with a frequency range from 3 hertz to 35 kilohertz is used for tuning the bandpass filter or oscillator. The dial readout, in Hz and CPM (cycles per minute), ad a range from 3 to 40 Hz and 180 to 2400 CPM. Frequency multiplication of X1, X10, X100 and X1K is provided by front-panel, self-cancelling pushbuttons.
above excerpts from 1977 TM 500 brochure and AF 501 BANDPASS FILTER Instruction Manual
FREQUENCY Hz, CPM Dial -- Variable from 3 to 40 in Hz range; 180 to 2400 in CPM (cycles per minute) range. Selects bandpass filter frequency or oscillator output frequency.
FREQ MULT Pushbutton -- Self-cancelling pushbuttons. Multiply the FREQUENCY Hz, CPM dial setting by the number shown on the depressed button to obtain bandpass filter tuning frequency or oscillator output frequency.
GAIN Switch -- Selects GAIN in AMPLIFIER (BROAD and NARROW) from 1 to 500 in a 1, 2, 5 sequence. Determines the output voltage in the OSCILLATOR mode (1, 2, or 5 volts only).
MODE Switch -- Selects AMPLIFIER, BROAD or NARROW BANDPASS FILTER, or OSCILLATOR operating mode.
INPUT Connector -- BNC connector for amplifier or bandpass filter signal input.
OUTPUT Connector -- BNC connector for amplifier, bandpass filter and oscillator output signal.
TRIG OUT Connector -- BNC connector for output pulse coincident with the frequency of the output signal. The TRIG OUT pulse in BANDPASS FILTER or OSCILLATOR mode can be used to accurately measure the frequency of a repetitive input signal with a counter.
POWER Indicator -- When lit, indicates power is applied.
The AF 501 may be used with a 10X voltage probe. Slew rate at the probe tip must not exceed 2.5 volts per microsevond. This is especially true when using a pulse for compensating the probe. If the slew rate limitation is exceeded, the input capacitance of the AF 501 is no longer constant making compensation impossible.
Bandpass Filter, Narrow and Broad
above excerpt from AF 501 BANDPASS FILTER Instruction Manual