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1657: Difference between revisions
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* [[Media:GenRad 1657 Manual 1657-0120-A 1657-0120-A 1978.pdf|GenRad 1657 Manual 1657-0120-A (1978)]] | * [[Media:GenRad 1657 Manual 1657-0120-A 1657-0120-A 1978.pdf|GenRad 1657 Manual 1657-0120-A (1978)]] | ||
* [https://www.ietlabs.com/pdf/Manuals/1657_im.pdf GenRad 1657 Manual] @ IET Labs | * [https://www.ietlabs.com/pdf/Manuals/1657_im.pdf GenRad 1657 Manual] @ IET Labs | ||
{{Catalog History}} | |||
}} | }} | ||
The '''General Radio 1657 Digibridge''' is a digital RLC meter, [[introduced in 1976]] [https://www.ietlabs.com/genrad_history/genrad_museum <sup>1</sup>]. | The '''General Radio 1657 Digibridge''' is a digital RLC meter, [[introduced in 1976]] [https://www.ietlabs.com/genrad_history/genrad_museum <sup>1</sup>]. | ||
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==Internals== | ==Internals== | ||
The 1657 applies a sine wave to the measured device and a precision resistor in series. The average voltage across each is measured using four different phases relative to the input sine wave, for a total of eight measurements. From these, the resistive and reactive components of the tested device | The 1657 applies a sine wave to the measured device and a precision resistor in series. | ||
The average voltage across each is measured using four different phases relative to the input sine wave, for a total of eight measurements. | |||
From these, the resistive and reactive components of the tested device are calculated and displayed. | |||
The 1657 uses a 6503 CPU, which is a 28-pin version of the 6502 with the same instruction set, but fewer address lines. | The 1657 uses a 6503 CPU, which is a 28-pin version of the 6502 with the same instruction set, but fewer address lines. | ||
The [http://www.tauntek.com/1657code.zip 1657's firmware] is contained in a 2Kx8 ROM, in later versions a 2716 EPROM. A 128-byte SRAM holds scratchpad and the stack. | |||
==Photos== | ==Photos== | ||