LMH6503 datasheet(18/20 Pages) NSC

18 / 20 page

Application Circuits

FOUR-QUADRANT MULTIPLIER

Applications requiring multiplication, squaring or other non-

linear functions can be implemented with four-quadrant mul-

tipliers. The LMH6503 implements a four-quadrant multiplier

as illustrated in Figure 11:

FREQUENCY SHAPING

Frequency

shaping

and

bandwidth

extension

the

LMH6503 can be accomplished using parallel networks con-

nected across the R

G ports. The network shown in the

Figure 12 schematic will effectively extend the LMH6503’s

bandwidth.

nd ORDER TUNABLE BANDPASS FILTER

The LMH6503 Variable-Gain Amplifier placed into a feed-

back loop provides signal processing function such as in a

2nd order tunable bandpass filter. The center frequency of

the 2nd order bandpass shown in Figure 13 is adjusted

through the use of the LMH6503’s gain control voltage, V

The integrators implemented with two sections of a

LMH6682, provide the coefficients for the transfer function.

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FIGURE 11. Four Quadrant Multiplier

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FIGURE 12. Frequency Shaping

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FIGURE 13. Tunable Bandpass Filter

LMH6503 Datasheet(PDF) 18 Page - National Semiconductor (TI)