This article introduces the features and advantages of the LTC1264-7 linear phase filter, which provides a better linear phase solution than Bessel filters.
The document introduces the LTC1264-7, a member of Linear Technology's Dash 7 family of linear phase filters. It highlights that this filter offers group delay equal to Bessel filters in the passband but provides significantly better stopband rejection (-30dB at the second harmonic versus -12dB for Bessel). The note explains that these filters integrate allpass and elliptic filtering poles within a single 14-pin package without requiring external resistors.
The text further discusses fundamental principles of data transmission, including Shannon's theorem limits on channel bandwidth and the use of multilevel Pulse Amplitude Modulation (PAM) to increase data rates. It explains how linear phase filters are critical for preserving pulse integrity in time-domain signals while providing necessary roll-off in the stopband to prevent interference between adjacent channels.
| Poles Configuration | 2 poles of phase compensation (allpass) and 6 poles of lowpass elliptic filtering |
|---|---|
| Package Type | 14-pin package |
| External Components Required | None |
| Stopband Rejection (2nd Harmonic) | -30dB |
The LTC1264-7 has the same group delay as a Bessel filter in the passband but offers -30dB rejection at the second harmonic, compared to only -12dB for Bessel.
No, it does not. The filter integrates all necessary poles in a single 14-pin package.
The LTC1264-7 will operate to 250kHz.