Switching noise

Aliead of this section is the EMI Alter. The design of the single-line dc Alter inductor is found in Section 3.5.7. This inductor has a relatively high value of dc current flowing through it and wants to isolate the high frequency switching noise from the input power bus. 

You are attempting to breadboard this circuit, you may need bypass capacitors (0.1 /xF capacitors from Vdd to the local IC ground) in order to minimize jitter and noise effects. These ICs switch at a very fast rate and can easily cause switching noise to appear on the outputs. 

The optimum characteristic impedance is dictated by a combination of factors. Interconnections with low characteristic impedance (<40 fl) cause high power dissipation and delay in driver circuits, increased switching noise, and reduced receiver noise tolerance (35). High characteristic impedance causes increased coupling noise and usually has higher loss. Generally, a characteristic impedance of 50-100 fl is optimal for most systems (35), and a ZQ of 50 fl has become standard for a variety of cables, connectors, and PWBs. For a polyimide dielectric with er = 3.5, a 50-fl stripline can be obtained with b = 50 xm, tv = 25 xm, and t = 5 xm. 

However, this charge pulse contains switching noise caused by the MOS-FETs. Since the linear image sensor have many Si ICs, this switching noise fluctuates because of nonuniformity in MOSFET characteristics. Therefore an efficient noise reduction technique is required for this sensor (Ozawa et al., 1982 Kaneko et al., 1982), as in the case of Si monolithic MOS image sensors (Ashikawa et al., 1973 Aoki et al., 1980). 

Impulse Noise Analysis Results. ANITA-lite measured about 130,000 distinct events, with an approximate rate of 5 events per minute. Fig. 6 shows examples of the major classes of impulsive noise encountered. The vast majority of triggered events are due to local payload interference such as switching noise from the Support Instrument Package. The duration of this class of events exceeds several hundred nanoseconds and a few events exhibit circular polarization for a portion of the pulse. The bottom two panes show an example of a synthetic pulse injected into the data stream to simulate a true signal event. The pulse is coherent and aligned across all channels. Preliminary studies of event selection procedures were conducted. They yield no passing events, while 97% of simulated Askaryan-induced impulses with amplitude 5<7 above noise survive (Miocinovic et al., 2004). 

If there was no filter present, the switching noise current received by the LISN would be... 

Signal generator, see function Signal to noise ratio, 74, 244 Simult. switch noise (SSN), 60 Sine, 77, 98, 112, 177, 182 Single phase ac, 220 Sinusoidal, 179 Slippage, 218 Slip rings, 219 Snubber,... 

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