Oregon USA - November 01, 2011
High Frequency Amplifier Noise
The measurement of Class-D and other PWM or Delta-Sigma digital modulator
type output stage amplifiers often presents a problem due to high frequency
switching noise components. These high frequency componenets can obstruct
the measurement of in-band typical 20-20kHz measurements.
these amplifiers have limited high frequency filtering of their own, and
many analyzers or other measuring instrumentation have no or insufficient
filtering to remove the passband effects of these strong high frequency
out-of-band components. The LF280™ offers a steep 80kHz 8th order passive
lowpass filter to remove these unwanted high frequency components and
enable accurate in-band amplifier response measurements.
The LF280™ is constructed entirely of the latest high linearity ultra
high permeability gapped Ferrite inductors and Polypropylene capacitors
for the ultimate in stability, high frequency performance, reduction of
high frequency loss, and maximum linearity. The LF280™ utilizes a unique
topology of identical component values to greatly reduce component sensitivity
and produce a highly stable response with maximum passband flatness.
common problem with any passive filter is loading by the external cable
capacitance or analyzer/meter input circuitry which can alter the passband
response. The LF280™ provides a precision R2R ladder attenuator which
effectively removes the effects of external device loading, and provides
a constant low output impedance regardless of the attenuation selected.
For attenuation levels of -12dB or lower the effects of any external device
loading are effectively eliminated. An additional advantage of the precision
attenuator is to reduce signal levels fed to other measuring devices which
may not be capable of handling the very large signals produced from high
product information and specifications subject to change without notice.
Complete product information will be provided on our web site for viewing/download
as soon as it becomes available at www.linearx.com. For sales contact
firstname.lastname@example.org for more details. ###